U.S. patent number 6,273,985 [Application Number 09/105,501] was granted by the patent office on 2001-08-14 for bonding process.
This patent grant is currently assigned to Xerox Corporation. Invention is credited to Lisa A. DeLouise, David J. Luca.
United States Patent |
6,273,985 |
DeLouise , et al. |
August 14, 2001 |
Bonding process
Abstract
Disclosed is a process for bonding a first article to a second
article which comprises (a) providing a first article comprising a
polymer having photosensitivity-imparting substituents; (b)
providing a second article comprising metal, plasma nitride,
silicon, or glass; (c) applying to at least one of the first
article and the second article an adhesion promoter selected from
silanes, titanates, or zirconates having (i) alkoxy, aryloxy, or
arylalkyloxy functional groups and (ii) functional groups including
at least one photosensitive aliphatic >C.dbd.C< linkage; (d)
placing the first article in contact with the second article; and
(e) exposing the first article, second article, and adhesion
promoter to radiation, thereby bonding the first article to the
second article with the adhesion promote. In one embodiment of the
present invention, the adhesion promoter is employed in
microelectrical mechanical systems such as thermal ink jet
printheads.
Inventors: |
DeLouise; Lisa A. (Rochester,
NY), Luca; David J. (Rochester, NY) |
Assignee: |
Xerox Corporation (Stamford,
CT)
|
Family
ID: |
22306211 |
Appl.
No.: |
09/105,501 |
Filed: |
June 26, 1998 |
Current U.S.
Class: |
156/273.3;
156/273.5; 156/275.5; 156/275.7; 430/286.1; 522/135; 522/172 |
Current CPC
Class: |
B41J
2/16 (20130101); B41J 2/1623 (20130101); B41J
2/1628 (20130101); B41J 2/1629 (20130101); B41J
2/1631 (20130101); B41J 2/1632 (20130101); B41J
2/1635 (20130101); B41J 2/1642 (20130101); B41J
2/1645 (20130101); C08J 5/124 (20130101); C09J
5/02 (20130101); C09J 2400/143 (20130101); C09J
2400/146 (20130101); C09J 2400/166 (20130101); C09J
2400/228 (20130101); C09J 2483/008 (20130101); G03F
7/038 (20130101); G03F 7/0388 (20130101); Y10T
428/2457 (20150115) |
Current International
Class: |
B41J
2/16 (20060101); C08J 5/12 (20060101); C09J
5/02 (20060101); G03F 7/038 (20060101); B32B
031/28 () |
Field of
Search: |
;156/273.3,273.5,275.1,275.3,275.5,275.7,330,327 ;522/135,172
;430/281.1,286.1,287.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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Primary Examiner: Ball; Michael W.
Assistant Examiner: Tolin; Michael A.
Attorney, Agent or Firm: Byorick; Judith L.
Claims
What is claimed is:
1. A process for bonding a first article to a second article which
comprises (a) providing a first article comprising a polymer having
photosensitivity-imparting substituents; (b) providing a second
article comprising metal, plasma nitride, silicon, or glass; (c)
applying to at least one of the first article and the second
article an adhesion promoter selected from silanes, titanates, or
zirconates having (i) alkoxy, aryloxy, or arylalkyloxy functional
groups and (ii) functional groups including at least one
photosensitive aliphatic >C.dbd.C< linkage; (d) placing the
first article in contact with the second article; and (e) exposing
the first article, second article, and adhesion promoter to
radiation, thereby bonding the first article to the second article
with the adhesion promoter.
2. A process according to claim 1 wherein the photosensitive
aliphatic >C.dbd.C< linkage is selected from the group
consisting of unsaturated esters, allyl groups, vinyl groups, and
mixtures thereof.
3. A process according to claim 1 wherein the adhesion promoter is
selected from the group consisting of those of the general
formulae
and
wherein M is Si, Ti, or Zr, x and y are each integers of 1, 2, or
3, wherein the sum of x+y is from 4 to 6, R.sub.1 is an alkyl
group, an aryl group, or an arylalkyl group, and R.sub.2 is an
unsaturated alkyl group or an unsaturated arylalkyl group.
4. A process according to claim 1 wherein the adhesion promoter is
selected from the group consisting of ##STR80##
and mixtures thereof.
5. A process according to claim 1 wherein the
photosensitivity-imparting substituents are selected from the group
consisting of unsaturated ester groups, alkylcarboxymethylene
groups, allyl groups, vinyl groups, unsaturated ether groups,
unsaturated ammonium groups, unsaturated phosphonium groups,
halomethyl groups, and mixtures thereof.
6. A process according to claim 1 wherein the polymer having
photosensitivity-imparting substituents is of the general formula
##STR81##
wherein x is an integer of 0 or 1, P is a substituent which imparts
photosensitivity to the polymer, a, b, c, and d are each integers
of 0, 1, 2, 3, or 4, provided that at least one of a, b, c, and d
is equal to or greater than 1 in at least some of the monomer
repeat units of the polymer, A is ##STR82##
or mixtures thereof, B is ##STR83##
wherein v is an integer of from 1 to about 20, ##STR84##
wherein z is an integer of from 2 to about 20, ##STR85##
wherein u is an integer of from 1 to about 20, ##STR86##
wherein w is an integer of from 1 to about 20, ##STR87##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units.
7. A process according to claim 6 wherein A is ##STR88##
wherein z is an integer of from 2 to about 20, or a mixture
thereof.
8. A process according to claim 1 wherein the radiation is heat,
electron beam radiation, ultraviolet light, x-ray radiation, or
mixtures thereof.
9. A process according to claim 1 wherein the radiation is
ultraviolet light.
10. A process for bonding a first article to a second article which
comprises (a) providing a first article comprising a polymer having
photosensitivity-imparting substituents and an adhesion promoter
selected from silanes, titanates, or zirconates having (i) alkoxy,
aryloxy, or arylalkyloxy functional groups and (ii) functional
groups including at least one photosensitive aliphatic
>C.dbd.C< linkage; (b) providing a second article comprising
metal, plasma nitride, silicon, or glass; (c) placing the first
article in contact with the second article; and (d) exposing the
first article and second article to radiation, thereby bonding the
first article to the second article.
11. A process according to claim 10 wherein the photosensitive
aliphatic >C.dbd.C< linkage is selected from the group
consisting of unsaturated esters, allyl groups, vinyl groups, and
mixtures thereof.
12. A process according to claim 10 wherein the adhesion promoter
is selected from the group consisting of those of the general
formulae
and
wherein M is Si, Ti, or Zr, x and y are each integers of 1, 2, or
3, wherein the sum of x+y is from 4 to 6, R.sub.1 is an alkyl
group, an aryl group, or an arylalkyl group, and R.sub.2 is an
unsaturated alkyl group or an unsaturated arylalkyl group.
13. A process according to claim 10 wherein the adhesion promoter
is selected from the group consisting of ##STR89##
and mixtures thereof.
14. A process according to claim 10 wherein the
photosensitivity-imparting substituents are selected from the group
consisting of unsaturated ester groups, alkylcarboxymethylene
groups, allyl groups, vinyl groups, unsaturated ether groups,
unsaturated ammonium groups, unsaturated phosphorium groups,
halomethyl groups, and mixtures thereof.
15. A process according to claim 10 wherein the polymer having
photosensitivity-imparting substituents is of the general formula
##STR90##
wherein x is an integer of 0 or 1, P is a substituent which imparts
photosensitivity to the polymer, a, b, c, and d are each integers
of 0, 1, 2, 3, or 4, provided that at least one of a, b, c, and d
is equal to or greater than 1 in at least some of the monomer
repeat units of the polymer, A is ##STR91##
or mixtures thereof, B is ##STR92##
wherein v is an integer of from 1 to about 20, ##STR93##
wherein z is an integer of from 2 to about 20, ##STR94##
wherein u is an integer of from 1 to about 20, ##STR95##
w herein w is an integer of from 1 to about 20, ##STR96##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units.
16. A process according to claim 15 wherein A is ##STR97##
wherein z is an integer of from 2 to about 20, or a mixture
thereof.
17. A process according to claim 10 wherein the radiation is heat,
electron beam radiation, ultraviolet light, x-ray radiation, or
mixtures thereof.
18. A process according to claim 10 wherein the radiation is
ultraviolet light.
Description
BACKGROUND OF THE INVENTION
The present invention is directed to a process for bonding articles
of specific polymers to other articles with an adhesion promoter.
More specifically, the present invention is directed to a process
for bonding an article comprising a polymer having
photosensitivity-imparting substituents to a second article
comprising metal, silicon, plasma nitride, or glass with an
adhesion promoter which is a titanium, zirconium, or silicon
compound. One embodiment of the present invention is directed to a
process for bonding a first article to a second article which
comprises (a) providing a first article comprising a polymer having
photosensitivity-imparting substituents; (b) providing a second
article comprising metal, plasma nitride, silicon, or glass; (c)
applying to at least one of the first article and the second
article an adhesion promoter selected from silanes, titanates, or
zirconates having (i) alkoxy, aryloxy, or arylalkyloxy functional
groups and (ii) functional groups including at least one
photosensitive aliphatic >C.dbd.C< linkage; (d) placing the
first article in contact with the second article; and (e) exposing
the first article, second article, and adhesion promoter to
radiation, thereby bonding the first article to the second article
with the adhesion promoter. Another embodiment of the present
invention is directed to an ink jet printhead which comprises (i)
an upper substrate with a set of parallel grooves for subsequent
use as ink channels and a recess for subsequent use as a manifold,
the grooves being open at one end for serving as droplet emitting
nozzles, (ii) a lower substrate in which one surface thereof has an
array of heating elements and addressing electrodes formed thereon,
at least a portion of said surface comprising metal, plasma
nitride, silicon, or glass, and (iii) an insulative layer deposited
on the surface of the lower substrate and over the heating elements
and addressing electrodes and patterned to form recesses
therethrough to expose the heating elements and terminal ends of
the addressing electrodes, the upper and lower substrates being
aligned, mated, and bonded together to form the printhead with the
grooves in the upper substrate being aligned with the heating
elements in the lower substrate to form droplet emitting nozzles,
said insulative layer comprising a crosslinked or chain extended
polymer wherein the crosslinking or chain extension is at least
partly through photosensitivity-imparting substituents; said
insulative layer being bonded to the surface of the lower substrate
with an adhesion promoter selected from silanes, titanates, or
zirconates having (a) alkoxy, aryloxy, or arylalkyloxy functional
groups and (b) functional groups including at least one
photosensitive aliphatic >C.dbd.C< linkage. Yet another
embodiment of the present invention is directed to a process for
forming an ink jet printhead which comprises (a) providing a lower
substrate in which one surface thereof has an array of heating
elements and addressing electrodes having terminal ends formed
thereon, at least a portion of said surface comprising metal,
plasma nitride, silicon, or glass; (b) depositing onto the surface
of the lower substrate having the heating elements and addressing
electrodes thereon an adhesion promoter selected from silanes,
titanates, or zirconates having (i) alkoxy, aryloxy, or
arylalkyloxy functional groups and (ii) functional groups including
at least one photosensitive aliphatic >C.dbd.C< linkage; (c)
depositing onto the surface of the lower substrate having the
adhesion promoter thereon an insulative layer comprising a polymer
having photosensitivity-imparting substituents, provided that the
R.sub.2 group of the adhesion promoter contains a functional group
which is capable of reacting with the material selected for the
insulative layer; (d) exposing the adhesion promoter and the
insulative layer to actinic radiation in an imagewise pattern such
that the polymer comprising the insulative layer in exposed areas
becomes crosslinked or chain extended and the polymer in unexposed
areas does not become crosslinked or chain extended, wherein the
unexposed areas correspond to areas of the lower substrate having
thereon the heating elements and the terminal ends of the
addressing electrodes, and wherein the insulative layer is bonded
to the lower substrate with the adhesion promoter in exposed areas;
(e) removing the adhesion promoter and the polymer from the
unexposed areas, thereby forming recesses in the layer, said
recesses exposing the heating elements and the terminal ends of the
addressing electrodes; (f) providing an upper substrate with a set
of parallel grooves for subsequent use as ink channels and a recess
for subsequent use as a manifold, the grooves being open at one end
for serving as droplet emitting nozzles; and (g) aligning, mating,
and bonding the upper and lower substrates together to form a
printhead with the grooves in the upper substrate being aligned
with the heating elements in the lower substrate to form droplet
emitting nozzles, thereby forming a thermal ink jet printhead.
Still another embodiment of the present invention is directed to an
ink jet printhead which comprises (i) an upper substrate with a set
of parallel grooves for subsequent use as ink channels and a recess
for subsequent use as a manifold, the grooves being open at one end
for serving as droplet emitting nozzles, (ii) a lower substrate in
which one surface thereof has an array of heating elements and
addressing electrodes formed thereon, at least a portion of said
surface comprising metal, plasma nitride, silicon, or glass, and
(iii) an insulative layer deposited on the surface of the lower
substrate and over the heating elements and addressing electrodes
and patterned to form recesses therethrough to expose the heating
elements and terminal ends of the addressing electrodes, the upper
and lower substrates being aligned, mated, and bonded together to
form the printhead with the grooves in the upper substrate being
aligned with the heating elements in the lower substrate to form
droplet emitting nozzles, said insulative layer comprising (a) a
crosslinked or chain extended polymer wherein the crosslinking or
chain extension is at least partly through
photosensitivity-imparting substituents, and (b) an adhesion
promoter selected from silanes, titanates, or zirconates having (1)
alkoxy, aryloxy, or arylalkyloxy functional groups and (2)
functional groups including at least one photosensitive aliphatic
>C.dbd.C< linkage. Another embodiment of the present
invention is directed to a process for forming an ink jet printhead
which comprises (a) providing a lower substrate in which one
surface thereof has an array of heating elements and addressing
electrodes having terminal ends formed thereon, at least a portion
of said surface comprising metal, plasma nitride, silicon, or
glass; (b) depositing onto the surface of the lower substrate an
insulative layer comprising (i) a polymer having
photosensitivity-imparting substituents, and (ii) an adhesion
promoter selected from silanes, titanates, or zirconates having (A)
alkoxy, aryloxy, or arylalkyloxy functional groups and (B)
functional groups including at least one photosensitive aliphatic
>C.dbd.C< linkage; (c) exposing the insulative layer to
actinic radiation in an imagewise pattern such that the polymer
comprising the insulative layer in exposed areas becomes
crosslinked or chain extended and the polymer in unexposed areas
does not become crosslinked or chain extended, wherein the
unexposed areas correspond to areas of the lower substrate having
thereon the heating elements and the terminal ends of the
addressing electrodes, and wherein the insulative layer is bonded
to the lower substrate in exposed areas; (d) removing the adhesion
promoter and the polymer from the unexposed areas, thereby forming
recesses in the layer, said recesses exposing the heating elements
and the terminal ends of the addressing electrodes; (e) providing
an upper substrate with a set of parallel grooves for subsequent
use as ink channels and a recess for subsequent use as a manifold,
the grooves being open at one end for serving as droplet emitting
nozzles; and (f) aligning, mating, and bonding the upper and lower
substrates together to form a printhead with the grooves in the
upper substrate being aligned with the heating elements in the
lower substrate to form droplet emitting nozzles, thereby forming a
thermal ink jet printhead.
In microelectronics applications, such as microelectrical
mechanical systems (MEMS), there is a great need for low dielectric
constant, high glass transition temperature, thermally stable,
photopatternable polymers for use as interlayer dielectric layers
and as passivation layers which protect microelectronic circuitry.
Poly(imides) are widely used to satisfy these needs; these
materials, however, have disadvantageous characteristics such as
relatively high water sorption and hydrolytic instability. There is
thus a need for high performance polymers which can be effectively
photopatterned and developed at high resolution.
One particular application for such materials is the fabrication of
ink jet printheads. Ink jet printing systems generally are of two
types: continuous stream and drop-on-demand. In continuous stream
ink jet systems, ink is emitted in a continuous stream under
pressure through at least one orifice or nozzle. The stream is
perturbed, causing it to break up into droplets at a flexed
distance from the orifice. At the break-up point, the droplets are
charged in accordance with digital data signals and passed through
an electrostatic field which adjusts the trajectory of each droplet
in order to direct it to a gutter for recirculation or a specific
location on a recording medium. In drop-on-demand systems, a
droplet is expelled from an orifice directly to a position on a
recording medium in accordance with digital data signals. A droplet
is not formed or expelled unless it is to be placed on the
recording medium.
Since drop-on-demand systems require no ink recovery, charging, or
deflection, the system is much simpler than the continuous stream
type. There are different types of drop-on-demand ink jet systems.
One type of drop-on-demand system has as its major components an
ink filled channel or passageway having a nozzle on one end and a
piezoelectric transducer near the other end to produce pressure
pulses. The relatively large size of the transducer prevents close
spacing of the nozzles, and physical limitations of the transducer
result in low ink drop velocity. Low drop velocity seriously
diminishes tolerances for drop velocity variation and
directionality, thus impacting the system's ability to produce high
quality copies. Drop-on-demand systems which use piezoelectric
devices to expel the droplets also suffer the disadvantage of a
slow printing speed.
The other type of drop-on-demand system is known as thermal ink
jet, or bubble jet, and produces high velocity droplets and allows
very close spacing of nozzles. The major components of this type of
drop-on-demand system are an ink filled channel having a nozzle on
one end and a heat generating resistor near the nozzle. Printing
signals representing digital information originate an electric
current pulse in a resistive layer within each ink passageway near
the orifice or nozzle, causing the ink in the immediate vicinity to
vaporize almost instantaneously and create a bubble. The ink at the
orifice is forced out as a propelled droplet as the bubble expands.
When the hydrodynamic motion of the ink stops, the process is ready
to start all over again. With the introduction of a droplet
ejection system based upon thermally generated bubbles, commonly
referred to as the "bubble jet" system, the drop-on-demand ink jet
printers provide simpler, lower cost devices than their continuous
stream counterparts, and yet have substantially the same high speed
printing capability.
The operating sequence of the bubble jet system begins with a
current pulse through the resistive layer in the ink filled
channel, the resistive layer being in close proximity to the
orifice or nozzle for that channel. Heat is transferred from the
resistor to the ink. The ink becomes superheated far above its
normal boiling point, and for water based ink, finally reaches the
critical temperature for bubble formation or nucleation of around
280.degree. C. Once nucleated, the bubble or water vapor thermally
isolates the ink from the heater and no further heat can be applied
to the ink. This bubble expands until all the heat stored in the
ink in excess of the normal boiling point diffuses away or is used
to convert liquid to vapor, which removes heat due to heat of
vaporization. The expansion of the bubble forces a droplet of ink
out of the nozzle, and once the excess heat is removed, the bubble
collapses. At this point, the resistor is no longer being heated
because the current pulse has passed and, concurrently with the
bubble collapse, the droplet is propelled at a high rate of speed
in a direction towards a recording medium. The surface of the
printhead encounters a severe cavitational force by the collapse of
the bubble, which tends to erode it. Subsequently, the ink channel
refills by capillary action. This entire bubble formation and
collapse sequence occurs in about 10 microseconds. The channel can
be refired after 100 to 500 microseconds minimum dwell time to
enable the channel to be refilled and to enable the dynamic
refilling factors to become somewhat dampened. Thermal ink jet
equipment and processes are well known and are described in, for
example, U.S. Pat. No. 4,601,777, U.S. Pat. No. 4,251,824, U.S.
Pat. No. 4,410,899, U.S. Pat. No. 4,412,224, U.S. Pat. No.
4,532,530, and U.S. Pat. No. 4,774,530, the disclosures of each of
which are totally incorporated herein by reference.
The present invention is suitable for ink jet printing processes,
including drop-on-demand systems such as thermal ink jet printing,
piezoelectric drop-on-demand printing, and the like.
In ink jet printing, a printhead is usually provided having one or
more ink-filled channels communicating with an ink supply chamber
at one end and having an opening at the opposite end, referred to
as a nozzle. These printheads form images on a recording medium
such as paper by expelling droplets of ink from the nozzles onto
the recording medium. The ink forms a meniscus at each nozzle prior
to being expelled in the form of a droplet. After a droplet is
expelled, additional ink surges to the nozzle to reform the
meniscus.
In thermal ink jet printing, a thermal energy generator, usually a
resistor, is located in the channels near the nozzles a
predetermined distance therefrom. The resistors are individually
addressed with a current pulse to momentarily vaporize the ink and
form a bubble which expels an ink droplet. As the bubble grows, the
ink bulges from the nozzle and is contained by the surface tension
of the ink as a meniscus. The rapidly expanding vapor bubble pushes
the column of ink filling the channel towards the nozzle. At the
end of the current pulse the heater rapidly cools and the vapor
bubble begins to collapse. However, because of inertia, most of the
column of ink that received an impulse from the exploding bubble
continues its forward motion and is ejected from the nozzle as an
ink drop. As the bubble begins to collapse, the ink still in the
channel between the nozzle and bubble starts to move towards the
collapsing bubble, causing a volumetric contraction of the ink at
the nozzle and resulting in the separation of the bulging ink as a
droplet. The acceleration of the ink out of the nozzle while the
bubble is growing provides the momentum and velocity of the droplet
in a substantially straight line direction towards a recording
medium, such as paper.
Ink jet printheads include an array of nozzles and may, for
example, be formed of silicon wafers using orientation dependent
etching (ODE) techniques. The use of silicon wafers is advantageous
because ODE techniques can form structures, such as nozzles, on
silicon wafers in a highly precise manner. Moreover, these
structures can be fabricated efficiently at low cost. The resulting
nozzles are generally triangular in cross-section. Thermal ink jet
printheads made by using the abovementioned ODE techniques
typically comprise a channel plate which contains a plurality of
nozzle-defining channels located on a lower surface thereof bonded
to a heater plate having a plurality of resistive heater elements
formed on an upper surface thereof and arranged so that a heater
element is located in each channel. The upper surface of the heater
plate typically includes an insulative layer which is patterned to
form recesses exposing the individual heating elements. This
insulative layer is referred to as a "pit layer" and is sandwiched
between the channel plate and heater plate. For examples of
printheads employing this construction, see U.S. Pat. No. 4,774,530
and U.S. Pat. No. 4,829,324, the disclosures of each of which are
totally incorporated herein by reference. Additional examples of
thermal ink jet printheads are disclosed in, for example, U.S. Pat.
No. 4,835,553, U.S. Pat. No. 5,057,853, and U.S. Pat. No.
4,678,529, the disclosures of each of which are totally
incorporated herein by reference.
In thermal ink jet printheads, polyimides are commonly used for
electronic passivation and for defining the fluid path. The
polyimide layer typically is bonded between the channel plate,
which frequently is fabricated of silicon, and the heater wafer. In
many instances, a trialkoxysilane based coupling agent is used to
promote adhesion of the polyimide to the heater wafer, which often
is passivated with materials such as phosphosilicate glass. The
principle mechanism by which the silane coupling agent works is
condensation of the silane with polar hydroxy groups that exist on
the phosphosilicate glass surface. Prior to deposition onto the
heater wafer substrate, the trialkoxysilane can be converted to the
trisilanol (HO).sub.3 SiR form. The silane is spin cast onto the
hydroxyl covered substrate and heated. The condensation reaction
produces water and/or alcohol reaction products when Si--O--Si
bonds form. Although Si--O--Si is a strong covalent bond, under
acidic or basic conditions the condensation/hydrolysis equilibrium
can be pushed toward hydrolysis, and delamination can occur. For
effective silane-based adhesion promotion, an adequate number of
substrate-polymer bonds must form in addition to a highly 2D or 3D
crosslinked siloxane network. In this instance, the probability
that all Si--O--Si bonds will hydrolyze simultaneously is
reduced.
U.S. Pat. No. 5,739,254, filed Aug. 29, 1996, entitled "Process for
Haloalkylation of High Performance Polymers," with the named
inventors Timothy J. Fuller, Ram S. Narang, Thomas W. Smith, David
J. Luca, and Raymond K. Crandall, and European Patent Publication
0,826,700, the disclosures of each of which are totally
incorporated herein by reference, disclose a process which
comprises reacting a polymer of the general formula ##STR1##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR2##
B is one of several specified groups, such as ##STR3##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units, with an acetyl halide and dimethoxymethane
in the presence of a halogen-containing Lewis acid catalyst and
methanol, thereby forming a haloalkylated polymer. In a specific
embodiment, the haloalkylated polymer is then reacted further to
replace at least some of the haloalkyl groups with
photosensitivity-imparting groups. Also disclosed is a process for
preparing a thermal ink jet printhead with the aforementioned
polymer.
U.S. Pat. No. 5,738,799, filed Sep. 12, 1996, the disclosure of
which is totally incorporated herein by reference, discloses an
ink-jet printhead fabrication technique which enables capillary
channels for liquid ink to be formed with square or rectangular
cross-sections. A sacrificial layer is placed over the main surface
of a silicon chip, the sacrificial layer being patterned in the
form of the void formed by the desired ink channels. A permanent
layer, comprising permanent material, is applied over the
sacrificial layer, and, after polishing the two layers to form a
uniform surface, the sacrificial layer is removed. Preferred
materials for the sacrificial layer include polyimide while
preferred materials for the permanent layer include polyarylene
ether, although a variety of material combinations are
possible.
Copending application U.S. Ser. No. 08/705,914, filed Aug. 29,
1996, entitled "Thermal Ink Jet Printhead With Ink Resistant Heat
Sink Coating," with the named inventors Ram S. Narang and Timothy
J. Fuller, the disclosure of which is totally incorporated herein
by reference, discloses a heat sink for a thermal ink jet printhead
having improved resistance to the corrosive effects of ink by
coating the surface of the heat sink with an ink resistant film
formed by electrophoretically depositing a polymeric material on
the heat sink surface. In one described embodiment, a thermal ink
jet printer is formed by bonding together a channel plate and a
heater plate. Resistors and electrical connections are formed in
the surface of the heater plate. The heater plate is bonded to a
heat sink comprising a zinc substrate having an electrophoretically
deposited polymeric film coating. The film coating provides
resistance to the corrosion of higher pH inks. In another
embodiment, the coating has conductive fillers dispersed
therethrough to enhance the thermal conductivity of the heat sink.
In one embodiment, the polymeric material is selected from the
group consisting of polyethersulfones, polysulfones, polyamides,
polyimides, polyamide-imides, epoxy resins, polyetherimides,
polyarylene ether ketones, chloromethylated polyarylene ether
ketones, acryloylated polyarylene ether ketones, polystyrene and
mixtures thereof.
Copending application U.S. Ser. No. 08/703,138, filed Aug. 29,
1996, entitled "Method for Applying an Adhesive Layer to a
Substrate Surface," with the named inventors Ram S. Narang, Stephen
F. Pond, and Timothy J. Fuller, the disclosure of which is totally
incorporated herein by reference, discloses a method for uniformly
coating portions of the surface of a substrate which is to be
bonded to another substrate. In a described embodiment, the two
substrates are channel plates and heater plates which, when bonded
together, form a thermal ink jet printhead. The adhesive layer is
electrophoretically deposited over a conductive pattern which has
been formed on the binding substrate surface. The conductive
pattern forms an electrode and is placed in an electrophoretic bath
comprising a colloidal emulsion of a preselected polymer adhesive.
The other electrode is a metal container in which the solution is
placed or a conductive mesh placed within the container. The
electrodes are connected across a voltage source and a field is
applied. The substrate is placed in contact with the solution, and
a small current flow is carefully controlled to create an extremely
uniform thin deposition of charged adhesive micelles on the surface
of the conductive pattern. The substrate is then removed and can be
bonded to a second substrate and cured. In one embodiment, the
polymer adhesive is selected from the group consisting of
polyamides, polyimides, polyamide-imides, epoxy resins,
polyetherimides, polysulfones, polyether sulfones, polyarylene
ether ketones, polystyrenes, chloromethylated polyarylene ether
ketones, acryloylated polyarylene ether ketones, and mixtures
thereof.
Copending application U.S. Ser. No. 08/697,750, filed Aug. 29,
1996, entitled "Electrophoretically Deposited Coating For the Front
Face of an Ink Jet Printhead," with the named inventors Ram S.
Narang, Stephen F. Pond, and Timothy J. Fuller, the disclosure of
which is totally incorporated herein by reference, discloses an
electrophoretic deposition technique for improving the
hydrophobicity of a metal surface, in one embodiment, the front
face of a thermal ink jet printhead. For this example, a thin metal
layer is first deposited on the front face. The front face is then
lowered into a colloidal bath formed by a fluorocarbon-doped
organic system dissolved in a solvent and then dispersed in a
non-solvent. An electric field is created and a small amount of
current through the bath causes negatively charged particles to be
deposited on the surface of the metal coating. By controlling the
deposition time and current strength, a very uniform coating of the
fluorocarbon compound is formed on the metal coating. The
electrophoretic coating process is conducted at room temperature
and enables a precisely controlled deposition which is limited only
to the front face without intrusion into the front face orifices.
In one embodiment, the organic compound is selected from the group
consisting of polyimides, polyamides, polyamide-imides,
polysulfones, polyarylene ether ketones, polyethersulfones,
polytetrafluoroethylenes, polyvinylidene fluorides,
polyhexafluoropropylenes, epoxies, polypentafluorostyrenes,
polystyrenes, copolymers thereof, terpolymers thereof, and mixtures
thereof.
Copending application U.S. Ser. No. 08/705,916, filed Aug. 29,
1996, entitled "Stabilized Graphite Substrates," with the named
inventors Gary A. Kneezel, Ram S. Narang, Timothy J. Fuller, and
Peter J. John, the disclosure of which is totally incorporated
herein by reference, discloses an apparatus which comprises at
least one semiconductor chip mounted on a substrate, said substrate
comprising a graphite member having electrophoretically deposited
thereon a coating of a polymeric material. In one embodiment, the
semiconductor chips are thermal ink jet printhead subunits. In one
embodiment, the polymeric material is of the general formula
##STR4##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR5##
B is one of several specified groups, such as ##STR6##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units.
Copending application U.S. Ser. No. 08/705,375, filed Aug. 29,
1996, entitled "Improved Curable Compositions," with the named
inventors Timothy J. Fuller, Ram S. Narang, Thomas W. Smith, David
J. Luca, and Ralph A. Mosher, and European Patent Publication
0,827,027, the disclosures of each of which are totally
incorporated herein by reference, disclose an improved composition
comprising a photopatternable polymer containing at least some
monomer repeat units with photosensitivity-imparting substituents,
said photopatternable polymer being of the general formula
##STR7##
wherein x is an integer of 0 or 1, A is one of several specified
groups such as ##STR8##
B is one of several specified groups, such as ##STR9##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units. Also disclosed is a process for preparing
a thermal ink jet printhead with the aforementioned polymer and a
thermal ink jet printhead containing therein a layer of a
crosslinked or chain extended polymer of the above formula.
Copending application U.S. Ser. No. 08/705,365, filed Aug. 29,
1996, entitled "Hydroxyalkylated High Performance Curable
Polymers," with the named inventors Ram S. Narang and Timothy J.
Fuller, and European Patent Publication 0,827,028, the disclosures
of each of which are totally incorporated herein by reference,
disclose a composition which comprises (a) a polymer containing at
least some monomer repeat units with photosensitivity-imparting
substituents which enable crosslinking or chain extension of the
polymer upon exposure to actinic radiation, said polymer being of
the formula ##STR10##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR11##
B is one of several specified groups, such as ##STR12##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units, wherein said photosensitivity-imparting
substituents are hydroxyalkyl groups; (b) at least one member
selected from the group consisting of photoinitiators and
sensitizers; and (c) an optional solvent. Also disclosed are
processes for preparing the above polymers and methods of preparing
thermal ink jet printheads containing the above polymers.
Copending application U.S. Ser. No. 08/705,488, filed Aug. 29,
1996, entitled "Improved High Performance Polymer Compositions,"
with the named inventors Thomas W. Smith, Timothy J. Fuller, Ram S.
Narang, and David J. Luca, and European Patent Publication
0,827,029, the disclosures of each of which are totally
incorporated herein by reference, disclose a composition comprising
a polymer with a weight average molecular weight of from about
1,000 to about 65,000, said polymer containing at least some
monomer repeat units with a first, photosensitivity-imparting
substituent which enables crosslinking or chain extension of the
polymer upon exposure to actinic radiation, said polymer also
containing a second, thermal sensitivity-imparting substituent
which enables further polymerization of the polymer upon exposure
to temperatures of about 140.degree. C. and higher, wherein the
first substituent is not the same as the second substituent, said
polymer being selected from the group consisting of polysulfones,
polyphenylenes, polyether sulfones, polyimides, polyamide imides,
polyarylene ethers, polyphenylene sulfides, polyarylene ether
ketones, phenoxy resins, polycarbonates, polyether imides,
polyquinoxalines, polyquinolines, polybenzimidazoles,
polybenzoxazoles, polybenzothiazoles, polyoxadiazoles, copolymers
thereof, and mixtures thereof.
Copending application U.S. Ser. No. 08/697,761, filed Aug. 29,
1996, entitled "Process for Direct Substitution of High Performance
Polymers with Unsaturated Ester Groups," with the named inventors
Timothy J. Fuller, Ram S. Narang, Thomas W. Smith, David J. Luca,
and Raymond K. Crandall, and European Patent Publication 0,827,030,
the disclosures of each of which are totally incorporated herein by
reference, disclose a process which comprises reacting a polymer of
the general formula ##STR13##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR14##
B is one of several specified groups, such as ##STR15##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units, with (i) a formaldehyde source, and (ii)
an unsaturated acid in the presence of an acid catalyst, thereby
forming a curable polymer with unsaturated ester groups. Also
disclosed is a process for preparing an ink jet printhead with the
above polymer.
Copending application U.S. Ser. No. 08/705,479, filed Aug. 29,
1996, entitled "Processes for Substituting Haloalkylated Polymers
With Unsaturated Ester, Ether, and Alkylcarboxymethylene Groups,"
with the named inventors Timothy J. Fuller, Ram S. Narang, Thomas
W. Smith, David J. Luca, and Raymond K. Crandall, and European
Patent Publication 0,827,026, the disclosures of each of which are
totally incorporated herein by reference, disclose a process which
comprises reacting a haloalkylated aromatic polymer with a material
selected from the group consisting of unsaturated ester salts,
alkoxide salts, alkylcarboxylate salts, and mixtures thereof,
thereby forming a curable polymer having functional groups
corresponding to the selected salt. Another embodiment of the
invention is directed to a process for preparing an ink jet
printhead with the curable polymer thus prepared.
Copending application U.S. Ser. No. 08/705,376, filed Aug. 29,
1996, entitled "Blends Containing Curable Polymers," with the named
inventors Ram S. Narang and Timothy J. Fuller, and European Patent
Publication 0,827,031, the disclosures of each of which are totally
incorporated herein by reference, disclose a composition which
comprises a mixture of (A) a first component comprising a polymer,
at least some of the monomer repeat units of which have at least
one photosensitivity-imparting group thereon, said polymer having a
first degree of photosensitivity-imparting group substitution
measured in milliequivalents of photosensitivity-imparting group
per gram and being of the general formula ##STR16##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR17##
B is one of several specified groups, such as ##STR18##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units, and (B) a second component which comprises
either (1) a polymer having a second degree of
photosensitivity-imparting group substitution measured in
milliequivalents of photosensitivity-imparting group per gram lower
than the first degree of photosensitivity-imparting group
substitution, wherein said second degree of
photosensitivity-imparting group substitution may be zero, wherein
the mixture of the first component and the second component has a
third degree of photosensitivity-imparting group substitution
measured in milliequivalents of photosensitivity-imparting group
per gram which is lower than the first degree of
photosensitivity-imparting group substitution and higher than the
second degree of photosensitivity-imparting group substitution, or
(2) a reactive diluent having at least one
photosensitivity-imparting group per molecule and having a fourth
degree of photosensitivity-imparting group substitution measured in
milliequivalents of photosensitivity-imparting group per gram,
wherein the mixture of the first component and the second component
has a fifth degree of photosensitivity-imparting group substitution
measured in milliequivalents of photosensitivity-imparting group
per gram which is higher than the first degree of
photosensitivity-imparting group substitution and lower than the
fourth degree of photosensitivity-imparting group substitution;
wherein the weight average molecular weight of the mixture is from
about 10,000 to about 50,000; and wherein the third or fifth degree
of photosensitivity-imparting group substitution is from about 0.25
to about 2 milliequivalents of photosensitivity-imparting groups
per gram of mixture. Also disclosed is a process for preparing a
thermal ink jet printhead with the aforementioned composition.
Copending application U.S. Ser. No. 08/705,372, filed Aug. 29,
1996, entitled "High Performance Curable Polymers and Processes for
the Preparation Thereof," with the named inventors Ram S. Narang
and Timothy J. Fuller, and European Patent Publication 0,827,033,
the disclosures of each of which are totally incorporated herein by
reference, disclose a composition which comprises a polymer
containing at least some monomer repeat units with
photosensitivity-imparting substituents which enable crosslinking
or chain extension of the polymer upon exposure to actinic
radiation, said polymer being of the formula ##STR19##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR20##
B is one of several specified groups, such as ##STR21##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units, wherein said photosensitivity-imparting
substituents are allyl ether groups, epoxy groups, or mixtures
thereof. Also disclosed are a process for preparing a thermal ink
jet printhead containing the aforementioned polymers and processes
for preparing the aforementioned polymers.
Copending application U.S. Ser. No. 08/705,490, filed Aug. 29,
1996, entitled "Halomethylated High Performance Curable Polymers,"
with the named inventors Ram S. Narang and Timothy J. Fuller, the
disclosure of which is totally incorporated herein by reference,
discloses a process which comprises the steps of (a) providing a
polymer containing at least some monomer repeat units with
halomethyl group substituents which enable crosslinking or chain
extension of the polymer upon exposure to a radiation source which
is electron beam radiation, x-ray radiation, or deep ultraviolet
radiation, said polymer being of the formula ##STR22##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR23##
B is one of several specified groups, such as ##STR24##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units, and (b) causing the polymer to become
crosslinked or chain extended through the
photosensitivity-imparting groups. Also disclosed is a process for
preparing a thermal ink jet printhead by the aforementioned curing
process.
Copending application U.S. Ser. No. 08/697,760, filed Aug. 29,
1996, entitled "Aqueous Developable High Performance Curable
Polymers," with the named inventors Ram S. Narang and Timothy J.
Fuller, and European Patent Publication 0,827,032, the disclosures
of each of which are totally incorporated herein by reference,
disclose a composition which comprises a polymer containing at
least some monomer repeat units with water-solubility-imparting
substituents and at least some monomer repeat units with
photosensitivity-imparting substituents which enable crosslinking
or chain extension of the polymer upon exposure to actinic
radiation, said polymer being of the formula ##STR25##
wherein x is an integer of 0 or 1, A is one of several specified
groups, such as ##STR26##
B is one of several specified groups, such as ##STR27##
or mixtures thereof, and n is an integer representing the number of
repeating monomer units. In one embodiment, a single functional
group imparts both photosensitivity and water solubility to the
polymer. In another embodiment, a first functional group imparts
photosensitivity to the polymer and a second functional group
imparts water solubility to the polymer. Also disclosed is a
process for preparing a thermal ink jet printhead with the
aforementioned polymers.
New photoresists have been discovered which can, in many instances,
provide results superior to polyimides. These photoresists include
polyarylene ethers, polyarylene ether ketones, polyarylene ether
sulfones, and the like. Accordingly, while known compositions and
processes are suitable for their intended purposes, a need remains
for adhesion promoters particularly suitable for use with
polyarylene photoresists. In addition, a need remains for adhesion
promoters suitable for use with a wide variety of polymeric
photoresists. Further, a need remains for adhesion promoters which
enable good interfacial adhesion of photopatternable polymer films
on surfaces such as metal, plasma nitride, silicon, and glass,
including glass doped with phosphorus and/or boron. Additionally, a
need remains for adhesion promoters which enable the formation of
protective layers and fluid paths in ink jet printheads that are
highly resistant to hydrolysis degradation. There is also a need
for ink jet printheads which are resistant to delamination when
exposed to aqueous inks having basic pH. In addition, a need
remains for adhesion promoters in photopatternable articles which
provide good layer adhesion during the development process during
which portions of the photopatternable material are removed in an
imagewise pattern, thereby reducing or eliminating undercutting and
floating images (wherein portions of the photopatternable material
which should remain intact become delaminated). Further, a need
remains for adhesion promoters which have surface energies and
surface characteristics that enable good wetting of the adhesion
promoter surface by photopatternable polymers.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide adhesion
promoters and ink jet printheads with the above noted
advantages.
It is another object of the present invention to provide adhesion
promoters particularly suitable for use with polyarylene
photoresists.
It is yet another object of the present invention to provide
adhesion promoters suitable for use with a wide variety of
polymeric photoresists.
It is still another object of the present invention to provide
adhesion promoters which enable good interfacial adhesion of
photopolymer films on surfaces such as metal, plasma nitride,
silicon, and glass, including glass doped with phosphorus and/or
boron.
Another object of the present invention is to provide adhesion
promoters which enable the formation of protective layers and fluid
paths in ink jet printheads that are highly resistant to hydrolysis
degradation.
Yet another object of the present invention is to provide ink jet
printheads which are resistant to delamination when exposed to
aqueous inks having basic pH.
Still another object of the present invention is to provide
adhesion promoters in photopatternable articles which provide good
layer adhesion during the development process during which portions
of the photopatternable material are removed in an imagewise
pattern, thereby reducing or eliminating undercutting and floating
images (wherein portions of the photopatternable material which
should remain intact become delaminated).
It is another object of the present invention to provide adhesion
promoters which have surface energies and surface characteristics
that enable good wetting of the adhesion promoter surface by
photopatternable polymers.
These and other objects of the present invention (or specific
embodiments thereof) can be achieved by providing a process for
bonding a first article to a second article which comprises (a)
providing a first article comprising a polymer having
photosensitivity-imparting substituents; (b) providing a second
article comprising metal, plasma nitride, silicon, or glass; (c)
applying to at least one of the first article and the second
article an adhesion promoter selected from silanes, titanates, or
zirconates having (i) alkoxy, aryloxy, or arylalkyloxy functional
groups and (ii) functional groups including at least one
photosensitive aliphatic >C.dbd.C< linkage; (d) placing the
first article in contact with the second article; and (e) exposing
the first article, second article, and adhesion promoter to
radiation, thereby bonding the first article to the second article
with the adhesion promoter. Another embodiment of the present
invention is directed to an ink jet printhead which comprises (i)
an upper substrate with a set of parallel grooves for subsequent
use as ink channels and a recess for subsequent use as a manifold,
the grooves being open at one end for serving as droplet emitting
nozzles, (ii) a lower substrate in which one surface thereof has an
array of heating elements and addressing electrodes formed thereon,
at least a portion of said surface comprising metal, plasma
nitride, silicon, or glass, and (iii) an insulative layer deposited
on the surface of the lower substrate and over the heating elements
and addressing electrodes and patterned to form recesses
therethrough to expose the heating elements and terminal ends of
the addressing electrodes, the upper and lower substrates being
aligned, mated, and bonded together to form the printhead with the
grooves in the upper substrate being aligned with the heating
elements in the lower substrate to form droplet emitting nozzles,
said insulative layer comprising a crosslinked or chain extended
polymer wherein the crosslinking or chain extension is at least
partly through photosensitivity-imparting substituents; said
insulative layer being bonded to the surface of the lower substrate
with an adhesion promoter selected from silanes, titanates, or
zirconates having (a) alkoxy, aryloxy, or arylalkyloxy functional
groups and (b) functional groups including at least one
photosensitive aliphatic >C.dbd.C< linkage. Yet another
embodiment of the present invention is directed to a process for
forming an ink jet printhead which comprises (a) providing a lower
substrate in which one surface thereof has an array of heating
elements and addressing electrodes having terminal ends formed
thereon, at least a portion of said surface comprising metal,
plasma nitride, silicon, or glass; (b) depositing onto the surface
of the lower substrate having the heating elements and addressing
electrodes thereon an adhesion promoter selected from silanes,
titanates, or zirconates having (i) alkoxy, aryloxy, or
arylalkyloxy functional groups and (ii) functional groups including
at least one photosensitive aliphatic >C.dbd.C< linkage; (c)
exposing the adhesion promoter and the insulative layer to actinic
radiation in an imagewise pattern such that the polymer comprising
the insulative layer in exposed areas becomes crosslinked or chain
extended and the polymer in unexposed areas does not become
crosslinked or chain extended, wherein the unexposed areas
correspond to areas of the lower substrate having thereon the
heating elements and the terminal ends of the addressing
electrodes, and wherein the insulative layer is bonded to the lower
substrate with the adhesion promoter in exposed areas; (d) removing
the adhesion promoter and the polymer from the unexposed areas,
thereby forming recesses in the layer, said recesses exposing the
heating elements and the terminal ends of the addressing
electrodes; (e) providing an upper substrate with a set of parallel
grooves for subsequent use as ink channels and a recess for
subsequent use as a manifold, the grooves being open at one end for
serving as droplet emitting nozzles; and (f) aligning, mating, and
bonding the upper and lower substrates together to form a printhead
with the grooves in the upper substrate being aligned with the
heating elements in the lower substrate to form droplet emitting
nozzles, thereby forming a thermal ink jet printhead. Still another
embodiment of the present invention is directed to an ink jet
printhead which comprises (i) an upper substrate with a set of
parallel grooves for subsequent use as ink channels and a recess
for subsequent use as a manifold, the grooves being open at one end
for serving as droplet emitting nozzles, (ii) a lower substrate in
which one surface thereof has an array of heating elements and
addressing electrodes formed thereon, at least a portion of said
surface comprising metal, plasma nitride, silicon, or glass, and
(iii) an insulative layer deposited on the surface of the lower
substrate and over the heating elements and addressing electrodes
and patterned to form recesses therethrough to expose the heating
elements and terminal ends of the addressing electrodes, the upper
and lower substrates being aligned, mated, and bonded together to
form the printhead with the grooves in the upper substrate being
aligned with the heating elements in the lower substrate to form
droplet emitting nozzles, said insulative layer comprising (a) a
crosslinked or chain extended polymer wherein the crosslinking or
chain extension is at least partly through
photosensitivity-imparting substituents, and (b) an adhesion
promoter selected from silanes, titanates, or zirconates having (1)
alkoxy, aryloxy, or arylalkyloxy functional groups and (2)
functional groups including at least one photosensitive aliphatic
>C.dbd.C< linkage. Another embodiment of the present
invention is directed to a process for forming an ink jet printhead
which comprises (a) providing a lower substrate in which one
surface thereof has an array of heating elements and addressing
electrodes having terminal ends formed thereon, at least a portion
of said surface comprising metal, plasma nitride, silicon, or
glass; (b) depositing onto the surface of the lower substrate an
insulative layer comprising (i) a polymer having
photosensitivity-imparting substituents, and (ii) an adhesion
promoter selected from silanes, titanates, or zirconates having (A)
alkoxy, aryloxy, or arylalkyloxy functional groups and (B)
functional groups including at least one photosensitive aliphatic
>C.dbd.C< linkage; (c) exposing the insulative layer to
actinic radiation in an imagewise pattern such that the polymer
comprising the insulative layer in exposed areas becomes
crosslinked or chain extended and the polymer in unexposed areas
does not become crosslinked or chain extended, wherein the
unexposed areas correspond to areas of the lower substrate having
thereon the heating elements and the terminal ends of the
addressing electrodes, and wherein the insulative layer is bonded
to the lower substrate in exposed areas; (d) removing the adhesion
promoter and the polymer from the unexposed areas, thereby forming
recesses in the layer, said recesses exposing the heating elements
and the terminal ends of the addressing electrodes; (e) providing
an upper substrate with a set of parallel grooves for subsequent
use as ink channels and a recess for subsequent use as a manifold,
the grooves being open at one end for serving as droplet emitting
nozzles; and (f) aligning, mating, and bonding the upper and lower
substrates together to form a printhead with the grooves in the
upper substrate being aligned with the heating elements in the
lower substrate to form droplet emitting nozzles, thereby forming a
thermal ink jet printhead.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an enlarged schematic isometric view of an example of a
printhead mounted on a daughter board showing the droplet emitting
nozzles.
FIG. 2 is an enlarged cross-sectional view of FIG. 1 as viewed
along the line 2--2 thereof and showing the electrode passivation
and ink flow path between the manifold and the ink channels.
FIG. 3 is an enlarged cross-sectional view of an alternate
embodiment of the printhead in FIG. 1 as viewed along the line 2--2
thereof.
DETAILED DESCRIPTION OF THE INVENTION
The process of the present invention can be used to bond any
article of a polymer having photosensitivity-imparting substituents
to a second article comprising metal, plasma nitride, silicon, or
glass. Any glass may be employed; preferred glasses include those
of silicon dioxide, silicon dioxide doped with phosphorus, silicon
dioxide doped with boron, and silicon dioxide doped with phosphorus
and boron. The adhesion promoter is applied to at least one of the
two articles, followed by exposing the two articles and the
adhesion promoter to radiation. Suitable radiation includes heat,
electron beam radiation, light, such as ultraviolet light, or the
like, with ultraviolet light being the preferred form of radiation.
Exposure to radiation is believed to initiate crosslinking or chain
extension of the polymer so that coupling occurs between the
photosensitivity-imparting groups on the polymer and the active
groups on the adhesion promoter, thereby forming a strong
interfacial bond. For example, the process of the present invention
can be used to bond together elements in microelectronic mechanical
devices, such as thermal ink jet printheads.
The printheads of the present invention can be of any suitable
configuration. An example of a suitable configuration, suitable in
this instance for thermal ink jet printing, is illustrated
schematically in FIG. 1, which depicts an enlarged, schematic
isometric view of the front face 29 of a printhead 10 showing the
array of droplet emitting nozzles 27. Referring also to FIG. 2,
discussed later, the lower electrically insulating substrate or
heating element plate 28 has the heating elements 34 and addressing
electrodes 33 patterned on surface 30 thereof, while the upper
substrate or channel plate 31 has parallel grooves 20 which extend
in one direction and penetrate through the upper substrate front
face edge 29. The other end of grooves 20 terminate at slanted wall
21, the floor 41 of the internal recess 24 which is used as the ink
supply manifold for the capillary filled ink channels 20, has an
opening 25 therethrough for use as an ink fill hole. The surface of
the channel plate with the grooves are aligned and bonded to the
heater plate 28, so that a respective one of the plurality of
heating elements 34 is positioned in each channel, formed by the
grooves and the lower substrate or heater plate. Ink enters the
manifold formed by the recess 24 and the lower substrate 28 through
the fill hole 25 and by capillary action, fills the channels 20 by
flowing through an elongated recess 38 formed in the thick film
insulative layer 18. The ink at each nozzle forms a meniscus, the
surface tension of which prevents the ink from weeping therefrom.
The addressing electrodes 33 on the lower substrate or channel
plate 28 terminate at terminals 32. The upper substrate or channel
plate 31 is smaller than that of the lower substrate in order that
the electrode terminals 32 are exposed and available for wire
bonding to the electrodes on the daughter board 19, on which the
printhead 10 is permanently mounted. Layer 18 is a thick film
passivation layer, discussed later, sandwiched between the upper
and lower substrates. This layer is etched to expose the heating
elements, thus placing them in a pit, and is etched to form the
elongated recess to enable ink flow between the manifold 24 and the
ink channels 20. In addition, the thick film insulative layer is
etched to expose the electrode terminals.
A cross sectional view of FIG. 1 is taken along view line 2--2
through one channel and shown as FIG. 2 to show how the ink flows
from the manifold 24 and around the end 21 of the groove 20 as
depicted by arrow 23. As is disclosed in U.S. Pat. No. 4,638,337,
U.S. Pat. No. 4,601,777, and U.S. Pat. No. Re. 32,572, the
disclosures of each of which are totally incorporated herein by
reference, a plurality of sets of bubble generating heating
elements 34 and their addressing electrodes 33 can be patterned on
the polished surface of a single side polished (100) silicon wafer.
Prior to patterning, the multiple sets of printhead electrodes 33,
the resistive material that serves as the heating elements 34, and
the common return 35, the polished surface of the wafer is coated
with an underglaze layer 39 such as silicon dioxide, having a
typical thickness of from about 5,000 Angstroms to about 2 microns,
although the thickness can be outside this range. The resistive
material can be a doped polycrystalline silicon, which can be
deposited by chemical vapor deposition (CVD) or any other well
known resistive material such as zirconium boride (ZrB.sub.2). The
common return and the addressing electrodes are typically aluminum
leads deposited on the underglaze and over the edges of the heating
elements. The common return ends or terminals 37 and addressing
electrode terminals 32 are positioned at predetermined locations to
allow clearance for wire bonding to the electrodes (not shown) of
the daughter board 19, after the channel plate 31 is attached to
make a printhead. The common return 35 and the addressing
electrodes 33 are deposited to a thickness typically of from about
0.5 to about 3 microns, although the thickness can be outside this
range, with the preferred thickness being 1.5 microns.
If polysilicon heating elements are used, they may be subsequently
oxidized in steam or oxygen at a relatively high temperature,
typically about 1,100.degree. C. although the temperature can be
above or below this value, for a period of time typically of from
about 50 to about 80 minutes, although the time period can be
outside this range, prior to the deposition of the aluminum leads,
in order to convert a small portion of the polysilicon to
SiO.sub.2. In such cases, the heating elements are thermally
oxidized to achieve an overglaze (not shown) of SiO.sub.2 with a
thickness typically of from about 500 Angstroms to about 1 micron,
although the thickness can be outside this range, which has good
integrity with substantially no pinholes.
In one embodiment, polysilicon heating elements are used and an
optional silicon dioxide thermal oxide layer 17 is grown from the
polysilicon in high temperature steam. The thermal oxide layer is
typically grown to a thickness of from about 0.5 to about 1 micron,
although the thickness can be outside this range, to protect and
insulate the heating elements from the conductive ink. The thermal
oxide is removed at the edges of the polysilicon heating elements
for attachment of the addressing electrodes and common return,
which are then patterned and deposited. If a resistive material
such as zirconium boride is used for the heating elements, then
other suitable well known insulative materials can be used for the
protective layer thereover. Before electrode passivation, a
tantalum (Ta) layer (not shown) can be optionally deposited,
typically to a thickness of about 1 micron, although the thickness
can be above or below this value, on the heating element protective
layer 17 for added protection thereof against the cavitational
forces generated by the collapsing ink vapor bubbles during
printhead operation. The tantalum layer is etched off all but the
protective layer 17 directly over the heating elements using, for
example, CF.sub.4 /O.sub.2 plasma etching. For polysilicon heating
elements, the aluminum common return and addressing electrodes
typically are deposited on the underglaze layer and over the
opposing edges of the polysilicon heating elements which have been
cleared of oxide for the attachment of the common return and
electrodes.
For electrode passivation, a film 16 is deposited over the entire
wafer surface, including the plurality of sets of heating elements
and addressing electrodes. The passivation film 16 provides an ion
barrier which will protect the exposed electrodes from the ink.
Examples of suitable ion barrier materials for passivation film 16
include polyimide, plasma nitride, silicon, glass (including but
not limited to silicon dioxide glasses), including glass doped with
phosphorus and/or boron, materials disclosed hereinafter as being
suitable for insulative layer 18, and the like, as well as any
combinations thereof. An effective ion barrier layer is generally
achieved when its thickness is from about 1000 Angstroms to about
10 microns, although the thickness can be outside this range. In
300 dpi printheads, passivation layer 16 preferably has a thickness
of about 3 microns, although the thickness can be above or below
this value. In 600 dpi printheads, the thickness of passivation
layer 16 preferably is such that the combined thickness of layer 16
and layer 18 is about 25 microns, although the thickness can be
above or below this value. The passivation film or layer 16 is
etched off of the terminal ends of the common return and addressing
electrodes for wire bonding later with the daughter board
electrodes. This etching of the silicon dioxide film con be by
either the wet or dry etching method. Alternatively, the electrode
passivation can be by plasma deposited silicon nitride (Si.sub.3
N.sub.4).
In one embodiment of the present invention, the adhesion promoter
is next applied to layer 16. The adhesion promoter can be spin cast
onto layer 16 from a solvent or mixture of solvents at an adhesion
promoter concentration of from about 0.005 to about 10 percent by
weight, and preferably from about 0.1 to about 1.0 percent by
weight, although the concentration can be outside of these ranges.
Typical solvents include water, methanol, isopropanol, glycol based
solvents such as butyl carbitol, cellusolve, methyl cellusolve,
xylene, N-methyl pyrrolidone, methyl ethyl ketone, and the like, as
well as mixtures thereof. Silane adhesion promoters are typically
cast from aqueous solvents, since hydrolysis of the alkoxy,
aryloxy, or arylalkyloxy groups to reactive groups on the surface
of layer 16 is desired. This result is best effected by reaction
with water prior to spin casting, although trialkoxy containing
silanes or partially hydrolyzed silanes may be directly applied to
the wafer. After spin casting, heat treatment of the silane layer
is typically carried out to effect the hydrolysis reaction of the
silanol groups with surface hydroxyls. Typically, the zirconate and
titanate adhesion promoters are already in the surface reactive
form and can be spin cast directly from solvent. Heat activation is
also not necessary with zirconate and titanate adhesion promoters,
and in situations wherein the adhesion promoter has many
photoactive groups, heat treatment can result in premature
crosslinking within the adhesion promoter layer prior to contacting
the insulating polymer layer 18. The spin rate and solution
concentrations are adjusted to produce an adhesion promoter layer
of the desired thickness. Typical adhesion promoter layer
thicknesses range from as low as a monolayer (less than about 10 to
about 100 nanometers) to many multilayers (about 0.5 to about 5.0
microns). Spin rates typically range from about 300 to about 3,000
rpm, and preferably from about 1,500 to about 2,000 rpm, although
the rate can be outside of these ranges. After spin casting the
silane adhesion promoter layer, the adhesion promoter typically is
heat activated for from about 5 to about 15 minutes, typically at
temperatures of from about 50 to about 100.degree. C., to effect
the bonding between the silane and layer 16.
In another embodiment of the present invention, the adhesion
promoter is added directly to the insulating polymer solution used
to form layer 18. In this instance, the optimum concentration of
adhesion promoter in the solution can be determined by the mole
fraction of the photoactive groups. Typically the adhesion promoter
concentration in the polymer solution is in from about 1 to about 5
mole excess of the photoactive groups on the backbone of the
photopatternable polymer monomers.
Next, a thick film type insulative layer 18, of a photopatternable
polymeric material discussed in further detail herein, is formed on
the passivation layer 16, typically having a thickness of from
about 10 to about 100 microns and preferably in the range of from
about 25 to about 50 microns, although the thickness can be outside
these ranges. Even more preferably, in 300 dpi printheads, layer 18
preferably has a thickness of about 30 microns, and in 600 dpi
printheads, layer 18 preferably has a thickness of from about 20 to
about 22 microns, although other thicknesses can be employed. The
insulative layer 18 is photolithographically processed to enable
etching and removal of those portions of the layer 18 over each
heating element (forming recesses 26), the elongated recess 38 for
providing ink passage from the manifold 24 to the ink channels 20,
and over each electrode terminal 32,37. Specifically, a mask is
applied to the surface of layer 18 and layer 18 (along with the
underlying adhesion promoter) is exposed to radiation at a
wavelength to which the photopatternable polymer is sensitive,
typically in the uv range. Subsequent to exposure, the areas of
layer 18 (and the underlying adhesion promoter) which were exposed
are crosslinked or chain extended and the areas of layer 18 (and
the underlying adhesion promoter) which were not exposed remain in
their original state and are easily removed. The elongated recess
38 is formed by the removal of this portion of the thick film layer
18. Thus, the passivation layer 16 alone protects the electrodes 33
from exposure to the ink in this elongated recess 38. Optionally,
if desired, insulative layer 18 can be applied as a series of thin
layers of either similar or different composition. Typically, a
thin layer is deposited, photoexposed, partially cured, followed by
deposition of the next thin layer, photoexposure, partial curing,
and the like. The thin layers constituting thick film insulative
layer 18 contain a polymer of the formula indicated hereinabove. In
one embodiment of the present invention, a first thin layer is
applied to contact layer 16, said first thin layer containing a
mixture of a polymer of the formula indicated hereinabove and an
epoxy polymer, followed by photoexposure, partial curing, and
subsequent application of one or more successive thin layers
containing a polymer of the formula indicated hereinabove.
FIG. 3 is a similar view to that of FIG. 2 with a shallow
anisotropically etched groove 40 in the heater plate, which is
silicon, prior to formation of the underglaze 39 and patterning of
the heating elements 34, electrodes 33 and common return 35. This
recess 40 permits the use of only the thick film insulative layer
18 and eliminates the need for the usual electrode passivating
layer 16. Since the thick film layer 18 is impervious to water and
relatively thick (typically from about 20 to about 40 microns,
although the thickness can be outside this range), contamination
introduced into the circuitry will be much less than with only the
relatively thin passivation layer 16 well known in the art. The
heater plate is a fairly hostile environment for integrated
circuits. Commercial ink generally entails a low attention to
purity. As a result, the active part of the heater plate will be at
elevated temperature adjacent to a contaminated aqueous ink
solution which undoubtedly abounds with mobile ions. In addition,
it is generally desirable to run the heater plate at a voltage of
from about 30 to about 50 volts, so that there will be a
substantial field present. Thus, the thick film insulative layer 18
provides improved protection for the active devices and provides
improved protection and a fluid path for the ink, resulting in
longer operating lifetime for the heater plate.
When a plurality of lower substrates 28 are produced from a single
silicon wafer, at a convenient point after the underglaze is
deposited, at least two alignment markings (not shown) preferably
are photolithographically produced at predetermined locations on
the lower substrates 28 which make up the silicon wafer. These
alignment markings are used for alignment of the plurality of upper
substrates 31 containing the ink channels. The surface of the
single sided wafer containing the plurality of sets of heating
elements is bonded to the surface of the wafer containing the
plurality of ink channel containing upper substrates subsequent to
alignment.
As disclosed in U.S. Pat. No. 4,601,777 and U.S. Pat. No.
4,638,337, the disclosures of each of which are totally
incorporated herein by reference, the channel plate is formed from
a two side polished, (100) silicon wafer to produce a plurality of
upper substrates 31 for the printhead. After the wafer is
chemically cleaned, a pyrolytic CVD silicon nitride layer (not
shown) is deposited on both sides. Using conventional
photolithography, a via for fill hole 25 for each of the plurality
of channel plates 31 and at least two vias for alignment openings
(not shown) at predetermined locations are printed on one wafer
side. The silicon nitride is plasma etched off of the patterned
vias representing the fill holes and alignment openings. A
potassium hydroxide (KOH) anisotropic etch can be used to etch the
fill holes and alignment openings. In this case, the [111] planes
of the (100) wafer typically make an angle of about 54.7 degrees
with the surface of the wafer. The fill holes are small square
surface patterns, generally of about 20 mils (500 microns) per
side, although the dimensions can be above or below this value, and
the alignment openings are from about 60 to about 80 mils (1.5 to 3
millimeters) square, although the dimensions can be outside this
range. Thus, the alignment openings are etched entirely through the
20 mil (0.5 millimeter) thick wafer, while the fill holes are
etched to a terminating apex at about halfway through to
three-quarters through the wafer. The relatively small square fill
hole is invariant to further size increase with continued etching
so that the etching of the alignment openings and fill holes are
not significantly time constrained.
Next, the opposite side of the wafer is photolithographically
pattered, using the previously etched alignment holes as a
reference to form the relatively large rectangular recesses 24 and
sets of elongated, parallel channel recesses that will eventually
become the ink manifolds and channels of the printheads. The
surface 22 of the wafer containing the manifold and channel
recesses are portions of the original wafer surface (covered by a
silicon nitride layer) on which an adhesive, such as a
thermosetting epoxy, will be applied later for bonding it to the
substrate containing the plurality of sets of heating elements. The
adhesive is applied in a manner such that it does not run or spread
into the grooves or other recesses. The alignment markings can be
used with, for example, a vacuum chuck mask aligner to align the
channel wafer on the heating element and addressing electrode
wafer. The two wafers are accurately mated and can be tacked
together by partial curing of the adhesive. Alternatively, the
heating element and channel wafers can be given precisely diced
edges and then manually or automatically aligned in a precision
jig. Alignment can also be performed with an infrared
aligner-bonder, with an infrared microscope using infrared opaque
markings on each wafer to be aligned, or the like. The two wafers
can then be cured in an oven or laminator to bond them together
permanently. The channel wafer can then be milled to produce
individual upper substrates. A final dicing cut, which produces end
face 29, opens one end of the elongated groove 20 producing nozzles
27. The other ends of the channel groove 20 remain closed by end
21. However, the alignment and bonding of the channel plate to the
heater plate places the ends 21 of channels 20 directly over
elongated recess 38 in the thick film insulative layer 18 as shown
in FIG. 2 or directly above the recess 40 as shown in FIG. 3
enabling the flow of ink into the channels from the manifold as
depicted by arrows 23. The plurality of individual printheads
produced by the final dicing are bonded to the daughter board and
the printhead electrode terminals are wire bonded to the daughter
board electrodes.
In one embodiment, a heater wafer with a phosphosilicate glass
layer is spin coated with a solution of one or more of the adhesion
promoters of the present invention (0.5 weight percent in methanol)
at 2,000 revolutions per minute for 30 seconds and air dried for
between 10 and 20 minutes before spin coating the photoresist
containing the photopatternable polymer onto the wafer at between
1,000 and 3,000 revolutions per minute for between 30 and 60
seconds. The photoresist solution is made by dissolving polyarylene
ether ketone with 0.75 acryloyl groups and 0.75 chloromethyl groups
per repeat unit and a weight average molecular weight of 25,000 in
N-methylpyrrolidinone at 40 weight percent solids with Michler's
ketone (1.2 parts ketone per every 10 parts of 40 weight percent
solids polymer solution). In another embodiment, the adhesion
promoter is added directly to the polymer film solution, and the
resulting solution is spin coated as described above. The film is
heated (soft baked) in an oven for between 10 and 15 minutes at
70.degree. C. After cooling to 25.degree. C. over 5 minutes, the
layered structure is covered with a mask and exposed to 365
nanometer ultraviolet light, amounting to between 150 and 1500
millijoules per cm.sup.2. The exposed wafer is then heated at
70.degree. C. for 2 minutes post exposure bake, followed by cooling
to 25.degree. C. over 5 minutes. The ultraviolet light exposure and
subsequent post exposure bake are believed to cause crosslinking of
the adhesion promoter to the polymer network. The film is developed
with 60:40 chloroform/cyclohexanone developer, washed with 90:10
hexanes/cyclohexanone, and then dried at 70.degree. C. for 2
minutes. A second developer/wash cycle is carried out if necessary
to obtain a wafer with clean features. The processed wafer is
transferred to an oven at 25.degree. C., and the oven temperature
is raised from 25 to 90.degree. C. at 2.degree. C. per minute. The
temperature is maintained at 90.degree. C. for 2 hours, and then
increased to 260.degree. C. at 2.degree. C. per minute. The oven
temperature is maintained at 260.degree. C. for 2 hours and then
the oven is turned off and the temperature is allowed to cool
gradually to 25.degree. C. When thermal cure of the photoresist
films is carried out under an inert atmosphere, such as nitrogen or
one of the noble gases, such as argon, neon, krypton, xenon, or the
like, there is markedly reduced oxidation of the developed film and
improved thermal and hydrolytic stability of the resultant devices.
Moreover, adhesion of developed photoresist film is improved to the
underlying substrate. If a second layer is spin coated over the
first layer, the heat cure of the first developed layer can be
stopped between 80 and 260.degree. C. before the second layer is
spin coated onto the first layer. A second thicker layer is
deposited by repeating the above procedure a second time. This
process is intended to be a guide in that procedures can be outside
the specified conditions depending on film thickness and
photoresist molecular weight. Films at 30 microns have been
developed with clean features at 600 dots per inch.
For best results with respect to well-resolved features and high
aspect ratios, photoresist compositions for printheads of the
present invention are free of particulates prior to coating onto
substrates. In one preferred embodiment, the photoresist
composition containing the photopatternable polymer is subjected to
filtration through a 2 micron nylon filter cloth (available from
Tetko). The photoresist solution is filtered through the cloth
under yellow light or in the dark as a solution containing from
about 30 to about 60 percent by weight solids using compressed air
(up to about 60 psi) and a pressure filtration funnel. No dilution
of the photoresist solution is required, and concentrations of an
inhibitor (such as, for example, MEHQ) can be as low as, for
example, 500 parts per million or less by weight without affecting
shelf life. No build in molecular weight of the photopatternable
polymer is observed during this filtration process. While not being
limited to any particular theory, it is believed that in some
instances, such as those when unsaturated ester groups are present
on the photopolymerizable polymer, compressed air yields results
superior to those obtainable with inert atmosphere because oxygen
in the compressed air acts as an effective inhibitor for the free
radical polymerization of unsaturated ester groups such as
acrylates and methacrylates.
In a particularly preferred embodiment, the photopatternable
polymer is admixed with an epoxy resin in relative amounts of from
about 75 parts by weight photopatternable polymer and about 25
parts by weight epoxy resin to about 90 parts by weight
photopatternable polymer and about 10 parts by weight epoxy resin.
Examples of suitable epoxy resins include EPON 1001 F, available
from Shell Chemical Co., Houston, Tex., believed to be of the
formula ##STR28##
and the like, as well as mixtures thereof. Curing agents of the
present invention as well as mixtures thereof can be used to cure
the epoxy resin at typical relative amounts of about 10 weight
percent curative per gram of epoxy resin solids. Process conditions
for the epoxy resin blended with the photopatternable polymer are
generally similar to those used to process the photoresist without
epoxy resin. Preferably, the epoxy or epoxy blend is selected so
that its curing conditions are different from the conditions
employed to apply, image, develop, and cure the photopatternable
polymer. Selective stepwise curing allows development of the
photoresist film before curing the epoxy resin to prevent unwanted
epoxy residues on the device. Incorporation of the epoxy resin into
the photopatternable polymer material improves the adhesion of the
photopatternable layer to the heater plate. Subsequent to imaging
and during cure of the photopatternable polymer, the epoxy reacts
with the heater layer to form strong chemical bonds with that
layer, improving adhesive strength and solvent resistance of the
interface. The presence of the epoxy may also improve the
hydrophilicity of the photopatternable polymer and thus may improve
the wetting properties of the layer, thereby improving the refill
characteristics of the printhead.
In one embodiment, the photopatternable polymer is of the general
formula ##STR29##
wherein x is an integer of 0 or 1, P is a substituent which imparts
photosensitivity to the polymer, a, b, c, and d are each integers
of 0, 1, 2, 3, or 4, provided that at least one of a, b, c, and d
is equal to or greater than 1 in at least some of the monomer
repeat units of the polymer, A is ##STR30##
or mixtures thereof, B is ##STR31##
wherein v is an integer of from 1 to about 20, and preferably from
1 to about 10, ##STR32##
wherein z is an integer of from 2 to about 20, and preferably from
2 to about 10, ##STR33##
wherein u is an integer of from 1 to about 20, and preferably from
1 to about 10, ##STR34##
wherein w is an integer of from 1 to about 20, and preferably from
1 to about 10, ##STR35##
other similar bisphenol derivatives, or mixtures thereof, and n is
an integer representing the number of repeating monomer units. The
value of n is such that the weight average molecular weight of the
material is from about 1,000 to about 100,000, preferably from
about 1,000 to about 65,000, more preferably from about 1,000 to
about 40,000, and even more preferably from about 3,000 to about
25,000, although the weight average molecular weight can be outside
these ranges. Preferably, n is an integer of from about 2 to about
70, more preferably from about 5 to about 70, and even more
preferably from about 8 to about 50, although the value of n can be
outside these ranges. The phenyl groups and the A and/or B groups
may also be substituted, although the presence of two or more
substituents on the B group ortho to the oxygen groups can render
substitution difficult. Substituents can be present on the polymer
either prior to or subsequent to the placement of
photosensitivity-imparting functional groups thereon. Substituents
can also be placed on the polymer during the process of placement
of photosensitivity-imparting functional groups thereon. Examples
of suitable substituents include (but are not limited to) alkyl
groups, including saturated, unsaturated, and cyclic alkyl groups,
preferably with from 1 to about 6 carbon atoms, substituted alkyl
groups, including saturated, unsaturated, and cyclic substituted
alkyl groups, preferably with from 1 to about 6 carbon atoms, aryl
groups, preferably with from 6 to about 24 carbon atoms,
substituted aryl groups, preferably with from 6 to about 24 carbon
atoms, arylalkyl groups, preferably with from 7 to about 30 carbon
atoms, substituted arylalkyl groups, preferably with from 7 to
about 30 carbon atoms, alkoxy groups, preferably with from 1 to
about 6 carbon atoms, substituted alkoxy groups, preferably with
from 1 to about 6 carbon atoms, aryloxy groups, preferably with
from 6 to about 24 carbon atoms, substituted aryloxy groups,
preferably with from 6 to about 24 carbon atoms, arylalkyloxy
groups, preferably with from 7 to about 30 carbon atoms,
substituted arylalkyloxy groups, preferably with from 7 to about 30
carbon atoms, hydroxy groups, amine groups, imine groups, ammonium
groups, pyridine groups, pyridinium groups, ether groups, ester
groups, amide groups, carbonyl groups, thiocarbonyl groups, sulfate
groups, sulfonate groups, sulfide groups, sulfoxide groups,
phosphine groups, phosphonium groups, phosphate groups, mercapto
groups, nitroso groups, sulfone groups, acyl groups, acid anhydride
groups, azide groups, and the like, wherein two or more
substituents can be joined together to form a ring, wherein the
substituents on the substituted alkyl groups, substituted aryl
groups, substituted arylalkyl groups, substituted alkoxy groups,
substituted aryloxy groups, and substituted arylalkyloxy groups can
be (but are not limited to) hydroxy groups, amine groups, imine
groups, ammonium groups, pyridine groups, pyridinium groups, ether
groups, aldehyde groups, ketone groups, ester groups, amide groups,
carboxylic acid groups, carbonyl groups, thiocarbonyl groups,
sulfate groups, sulfonate groups, sulfide groups, sulfoxide groups,
phosphine groups, phosphonium groups, phosphate groups, cyano
groups, nitrile groups, mercapto groups, nitroso groups, halogen
atoms, nitro groups, sulfone groups, acyl groups, acid anhydride
groups, azide groups, mixtures thereof, and the like, wherein two
or more substituents can be joined together to form a ring.
Processes for the preparation of these materials are known, and
disclosed in, for example, P. M. Hergenrother, J. Macromol. Sci.
Rev. Macromol. Chem., C19 (1), 1-34 (1980); P. M. Hergenrother, B.
J. Jensen, and S. J. Havens, Polymer, 29, 358 (1988); B. J. Jensen
and P. M. Hergenrother, "High Performance Polymers," Vol. 1, No. 1)
page 31 (1989), "Effect of Molecular Weight on Poly(arylene ether
ketone) Properties"; V. Percec and B. C. Auman, Makromol. Chem.
185, 2319 (1984); "High Molecular Weight Polymers by Nickel
Coupling of Aryl Polychlondes," I. Colon, G. T. Kwaiatkowski, J. of
Polymer Science, Part A, Polymer Chemistry, 28, 367 (1990); M. Ueda
and T. Ito, Polymer J., 23 (4), 297 (1991); "Ethynyl-Terminated
Polyarylates: Synthesis and Characterization," S. J. Havens and P.
M. Hergenrother, J. of Polymer Science: Polymer Chemistry Edition,
22, 3011 (1984); "Ethynyl-Terminated Polysulfones: Synthesis and
Characterization," P. M. Hergenrother, J. of Polymer Science:
Polymer Chemistry Edition, 20, 3131 (1982); K. E. Dukes, M. D.
Forbes, A. S. Jeevarajan, A. M. Belu, J. M. DeDimone, R. W. Linton,
and V. V. Sheares, Macromolecules, 29, 3081 (1996); G. Hougham, G.
Tesoro, and J. Shaw, Polym. Mater. Sci. Eng., 61, 369 (1989); V.
Percec and B. C. Auman, Makromol. Chem, 185, 617 (1984); "Synthesis
and characterization of New Fluorescent Poly(arylene ethers)," S.
Matsuo, N. Yakoh, S. Chino, M. Mitani, and S. Tagami, Journal of
Polymer Science: Part A: Polymer Chemistry, 32, 1071 (1994);
"Synthesis of a Novel Naphthalene-Based Poly(arylene ether ketone)
with High Solubility and Thermal Stability," Mami Ohno, Toshikazu
Takata, and Takeshi Endo, Macromolecules, 27, 3447 (1994);
"Synthesis and Characterization of New Aromatic Polyfether
ketones)," F. W. Mercer, M. T. Mckenzie, G. Merlino, and M. M.
Fone, J. of Applied Polymer Science, 56, 1397 (1995); H. C. Zhang,
T. L. Chen, Y. G. Yuan, Chinese Patent CN 85108751 (1991); "Static
and laser light scattering study of novel thermoplastics. 1.
Phenolphthalein poly(aryl ether ketone)," C. Wu, S. Bo, M. Siddiq,
G. Yang and T. Chen, Macromolecules, 29, 2989 (1996); "Synthesis of
t-Butyl-Substituted Poly(ether ketone) by Nickel-Catalyzed Coupling
Polymerization of Aromatic Dichloride", M. Ueda, Y. Seino, Y.
Haneda, M. Yoneda, and J.-I. Sugiyama, Journal of Polymer Science:
Part A: Polymer Chemistry, 32, 675 (1994); "Reaction Mechanisms:
Comb-like Polymers and Graft Copolymers from Macromers 2.
Synthesis, Characterzation and Homopolymerization of a Styrene
Macromer of Poly(2,6-dimethyl-1,4-phenylene Oxide)," V. Percec, P.
L. Rinaldi, and B. C. Auman, Polymer Bulletin, 10, 397 (1983);
Handbook of Polymer Synthesis Part A, Hans R. Kricheldorf, ed.,
Marcel Dekker, Inc., New York-Basel-Hong Kong (1992); and
"Introduction of Carboxyl Groups into Crosslinked Polystyrene," C.
R. Harrison, P. Hodge, J. Kemp, and G. M. Perry, Die
Makromolekulare Chemie, 176, 267 (1975), the disclosures of each of
which are totally incorporated herein by reference. Further
background on high performance polymers is disclosed in, for
example, U.S. Pat. No. 2,822,351; U.S. Pat. No. 3,065,205; British
Patent 1,060,546; British Patent 971,227; British Patent 1,078,234;
U.S. Pat. No. 4,175,175; N. Yoda and H. Hiramoto, J. Macromol.
Sci.-Chem., A21(13 & 14) pp. 1641 (1984) (Toray Industries,
Inc., Otsu, Japan; B. Sillion and L. Verdet, "Polyimides and other
High-Temperature polymers", edited by M. J. M. Abadie and B.
Sillion, Elsevier Science Publishers B.V. (Amsterdam 1991);
"Polyimides with Alicyclic Diamines. II. Hydrogen Abstraction and
Photo crosslinking Reactions of Benzophenone Type Polyimides," Q.
Jin, T. Yamashita, and K. Horie, J. of Polymer Science: Part A:
Polymer Chemistry, 32, 503 (1994); Probimide.TM. 300, product
bulletin, Ciba-Geigy Microelectronics Chemicals, "Photosensitive
Polyimide System;" High Performance Polymers and Composites, J. I.
Kroschwitz (ed.), John Wiley & Sons (New York 1991); and T. E.
Atwood, D. A. Barr, T. A. King, B. Newton, and B. J. Rose, Polymer,
29, 358 (1988), the disclosures of each of which are totally
incorporated herein by reference. Further information on radiation
curing is disclosed in, for example, Radiation Curing: Science and
Technology, S. Peter Pappas, ed., Plenum Press (New York 1992), the
disclosure of which is totally incorporated herein by reference.
Polymers of these formulae, the preparation thereof, and the use
thereof as photopatternable polymers in layer 18 of thermal ink jet
printheads are disclosed in, for example, U.S. Pat. No. 5,739,254,
copending application U.S. Ser. No. 08/705,375, filed Aug. 29,
1996, copending application U.S. Ser. No. 08/705,365, filed Aug.
29, 1996, copending application U.S. Ser. No. 08/705,488, filed
Aug. 29, 1996, copending application U.S. Ser. No. 08/697,761,
filed Aug. 29, 1996, copending application U.S. Ser. No.
08/705,479, filed Aug. 29, 1996, copending application U.S. Ser.
No. 08/705,376, filed Aug. 29, 1996, copending application U.S.
Ser. No. 08/705,372, filed Aug. 29, 1996, copending application
U.S. Ser. No. 08/705,490, filed Aug. 29, 1996, copending
application U.S. Ser. No. 08/697,760, filed Aug. 29, 1996,
copending application U.S. Ser. No. 08/920,240, filed Aug. 28,
1997, European Patent Publication 0,826,700, European Patent
Publication 0,827,027, European Patent Publication 0,827,028,
European Patent Publication 0,827,029, European Patent Publication
0,827,030, European Patent Publication 0,827,026, European Patent
Publication 0,827,031, European Patent Publication 0,827,033, and
European Patent Publication 0,827,032, the disclosures of each of
which are totally incorporated herein by reference.
Examples of suitable "P" groups include (but are not limited to)
unsaturated ester groups, such as acryloyl groups, methacryloyl
groups, glycidyl methacryloyl groups, cinnamoyl groups, crotonoyl
groups, ethacryloyl groups, oleoyl groups, linoleoyl groups,
maleoyl groups, fumaroyl groups, itaconoyl groups, citraconoyl
groups, phenylmaleoyl groups, esters of 3-hexene-1,6-dicarboxylic
acid, and the like, with an example illustrated below for acryloyl
groups, ##STR36##
wherein a, b, c, and d are each integers of 0, 1, 2, 3, or 4,
provided that at least one of a, b, c, and d is equal to or greater
than 1 in at least some of the monomer repeat units of the polymer,
and n is an integer representing the number of repeating monomer
units, alkylcarboxymethylene groups, of the above formula wherein
the ##STR37##
groups shown above are replaced with, for example, ##STR38##
groups, wherein R is an alkyl group (including saturated,
unsaturated, and cyclic alkyl groups), preferably with from 1 to
about 30 carbon atoms, more preferably with from 1 to about 6
carbon atoms, a substituted alkyl group, an aryl group, preferably
with from 6 to about 30 carbon atoms, more preferably with from 1
to about 2 carbon atoms, a substituted aryl group, an arylalkyl
group, preferably with from 7 to about 35 carbon atoms, more
preferably with from 7 to about 15 carbon atoms, or a substituted
arylalkyl group, wherein the substituents on the substituted alkyl,
aryl, and arylalkyl groups can be (but are not limited to) alkoxy
groups, preferably with from 1 to about 6 carbon atoms, aryloxy
groups, preferably with from 6 to about 24 carbon atoms,
arylalkyloxy groups, preferably with from 7 to about 30 carbon
atoms, hydroxy groups, amine groups, imine groups, ammonium groups,
pyridine groups, pyridinium groups, ether groups, ester groups,
amide groups, carbonyl groups, thiocarbonyl groups, sulfate groups,
sulfonate groups, sulfide groups, sulfoxide groups, phosphine
groups, phosphonium groups, phosphate groups, mercapto groups,
nitroso groups, sulfone groups, acyl groups, acid anhydride groups,
azide groups, and the like, wherein two or more substituents can be
joined together to form a ring, allyl groups, vinyl groups, and
unsaturated ether groups, of the above formula wherein the groups
shown above are replaced with, for example, ##STR39##
groups shown above are replaced with, for example, ##STR40##
groups, unsaturated ammonium groups and unsaturated phosphonium
groups, of the above formula wherein the ##STR41##
groups shown above are replaced with, for example, ##STR42##
groups or similar phosphonium groups, and the like. Under certain
conditions, such as imaging with electron beam, deep ultraviolet,
or x-ray radiation, polymers having haloalkyl groups (with
halomethyl groups being preferred), of the general formula
##STR43##
wherein n is an integer of 1, 2, 3, 4, or 5, R is an alkyl group,
including both saturated, unsaturated, linear, branched, and cyclic
alkyl groups, preferably with from 1 to about 11 carbon atoms, more
preferably with from 1 to about 5 carbon atoms, even more
preferably with from 1 to about 3 carbon atoms, and most preferably
with 1 carbon atom, or a substituted alkyl group, an arylalkyl
group, preferably with from 7 to about 29 carbon atoms, more
preferably with from 7 to about 17 carbon atoms, even more
preferably with from 7 to about 13 carbon atoms, and most
preferably with from 7 to about 9 carbon atoms, or a substituted
arylalkyl group, and X is a halogen atom, such as fluorine,
chlorine, bromine, or iodine, a, b, c, and d are each integers of
0, 1, 2, 3, or 4, provided that at least one of a, b, c, and d is
equal to or greater than 1 in at least some of the monomer repeat
units of the polymer, and n is an integer representing the number
of repeating monomer units, are also photoactive.
The degree of substitution of the polymer with the
photosensitivity-imparting substituents (i.e., the average number
of photosensitivity-imparting substituents per monomer repeat unit)
preferably is from about 0.25 to about 1.2, and more preferably
from about 0.65 to about 0.8, although the degree of substitution
can be outside these ranges. This degree of substitution generally
corresponds to from about 0.5 to about 1.3 milliequivalents of
photosensitivity-imparting substituent per gram of resin.
In another embodiment, the polymer of the above formula is
substituted with two different functional groups, one of which
imparts photosensitivity to the polymer and one of which imparts
water solubility or water dispersability to the polymer. Examples
of reactants which can be reacted with the polymer to substitute
the polymer with suitable water solubility enhancing groups or
water dispersability enhancing groups include tertiary amines, of
the general formula ##STR44##
which add to the polymer quaternary ammonium groups, of the general
formula ##STR45##
wherein R.sub.1, R.sup.2, and R.sub.3 each, independently of the
others, can be (but are not limited to) alkyl groups, typically
with from 1 to about 30 carbon atoms, substituted alkyl groups,
aryl groups, typically with from 6 to about 18 carbon atoms,
substituted aryl groups, arylalkyl groups, typically with from 7 to
about 19 carbon atoms, and substituted arylalkyl groups, and X
represents a halogen atom, such as fluorine, chlorine, bromine, or
iodine; tertiary phosphines, of the general formula ##STR46##
which add to the polymer quaternary phosphonium groups of the
general formula ##STR47##
wherein R.sub.1, R.sub.2, and R.sub.3 each, independently of the
others, can be (but are not limited to) alkyl groups, typically
with from 1 to about 30 carbon atoms, substituted alkyl groups,
aryl groups, typically with from 6 to about 18 carbon atoms,
substituted aryl groups, arylalkyl groups, typically with from 7 to
about 19 carbon atoms, and substituted arylalkyl groups, and X
represents a halogen atom, such as fluorine, chlorine, bromine, or
iodine; alkyl thio ethers, of the general formula ##STR48##
which add to the polymer sulfonium groups of the general formula
##STR49##
wherein R.sub.1 and R.sub.2 each, independently of the other, can
be (but are not limited to) alkyl groups, typically with from 1 to
about 6 carbon atoms and preferably with 1 carbon atom, and
substituted alkyl groups, and X represents a halogen atom, such as
fluorine, chlorine, bromine, or iodine; wherein the substituents on
the substituted alkyl, aryl, and arylalkyl groups can be (but are
not limited to) hydroxy groups, amine groups, imine groups,
ammonium groups, pyridine groups, pyridinium groups, ether groups,
aldehyde groups, ketone groups, ester groups, amide groups,
carboxylic acid groups, carbonyl groups, thiocarbonyl groups,
sulfate groups, sulfonate groups, sulfide groups, sulfoxide groups,
phosphine groups, phosphonium groups, phosphate groups, cyano
groups, nitrile groups, mercapto groups, nitroso groups, halogen
atoms, nitro groups, sulfone groups, acyl groups, acid anhydride
groups, azide groups, mixtures thereof, and the like, wherein two
or more substituents can be joined together to form a ring. The
degree of substitution (i.e., the average number of water
solubility imparting groups or water dispersability imparting
groups per monomer repeat unit) typically is from about 0.25 to
about 4.0, and preferably from about 0.5 to about 2, although the
degree of substitution can be outside these ranges. Optimum amounts
of substitution are from about 0.8 to about 2 milliequivalents of
water solubility imparting group or water dispersability imparting
group per gram of resin, and preferably from about 1 to about 1.5
milliequivalents of water solubility imparting group or water
dispersability imparting group per gram of resin.
In one specific embodiment, the photopatternable polymer has both
halomethyl substituents, such as chloromethyl groups, bromomethyl
groups, or the like, and other photosensitivity-imparting groups,
such as unsaturated ester groups, including acryloyl groups,
methacryloyl groups, or the like, and is illustrated below for the
embodiment with chloromethyl groups and acryloyl groups:
##STR50##
wherein e, f, g, h, i, j, k, and m are each integers of 0, 1, 2, 3,
or 4, provided that the sum of i+e is no greater than 4, the sum of
j+f is no greater than 4, the sum of k+g is no greater than 4, and
the sum of m+h is no greater than 4, and provided that at least one
of e, f, g, and h is equal to at least 1 in at least some of the
monomer repeat units of the polymer, and n is an integer
representing the number of repeating monomer units. In this
instance, the polymer typically has a degree of substitution of
from about 0.25 to about 2.25, preferably from about 0.75 to about
2, and more preferably from about 0.75 to about 1 halomethyl group
per monomer repeat unit, and from about 0.25 to about 1.5,
preferably from about 0.5 to about 0.8, and more preferably about
0.75 of the other photosensitivity-imparting groups per monomer
repeat unit, although the relative amounts can be outside these
ranges.
Blends of polymers can also be employed, provided that at least one
of the polymers contains photosensitivity-imparting substituents.
Blends of polymers preferably contain at least 25 percent by weight
of the polymer having photosensitivity-imparting substituents.
The adhesion promoters of the present invention are selected from
silanes, titanates, or zirconates having (a) alkoxy, aryloxy, or
arylalkyloxy functional groups and (b) functional groups including
at least one photosensitive aliphatic >C.dbd.C< linkage.
Examples of photosensitive aliphatic >C.dbd.C< linkage
containing groups include unsaturated esters, such as acrylates,
methacrylates, glycidyl acrylates and methacrylates, and the like,
allyl groups, vinyl groups, and the like. In one embodiment, the
silanes, titanates, and zirconates are of the general formula
or
wherein M is Si, Ti, or Zr, x and y are each integers of 1, 2, or
3, wherein the sum of x+y is from 4 to 6, R.sub.1 is an alkyl
group, including long chain, branched, cyclic, saturated,
unsaturated, and substituted alkyl groups, typically with from 1 to
about 20 carbon atoms, and preferably with from 1 to about 15
carbon atoms, although the number can be outside of these ranges,
an aryl group, including substituted aryl groups, typically with
from 6 to about 24 carbon atoms, and preferably with from 6 to
about 12 carbon atoms, although the number can be outside of these
ranges, or an arylalkyl group, including substituted arylalkyl
groups, typically with from 7 to about 28 carbon atoms, and
preferably with from 7 to about 15 carbon atoms, although the
number can be outside of these ranges, and R.sub.2 is an
unsaturated alkyl group, including long chain, branched, cyclic,
and substituted unsaturated alkyl groups, typically with from 2 to
about 20 carbon atoms, and preferably with from 2 to about 15
carbon atoms, although the number can be outside of these ranges,
or an unsaturated arylalkyl group, including substituted
unsaturated arylalkyl groups, typically with from 8 to about 28
carbon atoms, and preferably with from 8 to about 15 carbon atoms,
although the number can be outside of these ranges, wherein
examples of substituents which can be present on the substituted
alkyl, aryl, and arylalkyl groups include (but are not limited to)
hydroxy groups, amine groups, imine groups, ammonium groups,
pyridine groups, pyridinium groups, ether groups, aldehyde groups,
ketone groups, ester groups, amide groups, carboxylic acid groups,
carbonyl groups, thiocarbonyl groups, sulfate groups, sulfonate
groups, sulfide groups, sulfoxide groups, phosphine groups,
phosphonium groups, phosphate groups, cyano groups, nitrile groups,
mercapto groups, nitroso groups, halogen atoms, nitro groups,
sulfone groups, acyl groups, acid anhydride groups, azide groups,
mixtures thereof, and the like, wherein two or more substituents
can be joined together to form a ring. Generally, the OR.sub.1
group reacts with the article of metal, plasma nitride, silicon, or
glass by, for example, hydrolysis or solvolysis to form an
organofunctional monolayer, and the R.sub.2 group reacts with the
article comprising the photopatternable polymer. Further
information on adhesion promoters is disclosed in, for example,
"Factors Affecting Adhesion of Uithographic Materials," K. L.
Mittal, Solid State Technology, p. 89 (May 1979); "Hydrolysis,
Adsorption, and Dynamics of Silane Coupling Agents on Silica
Surfaces;" F. D. Blum et al., J. Adhesion Sci. Technol., Vol. 5.
No. 6, pp. 479-296 (1991); and "The Theory of Organo Titanate
Coupling Agents," S. J. Monte et al., SPE ANTEC, p. 27, Apr. 26-29,
1976, Atlantic City, N.J.; the disclosures of each of which are
totally incorporated herein by reference.
Specific examples of suitable adhesion promoters for the present
invention include NZ39, available from Kenrich, Inc., Bayonne,
N.J., of the formula ##STR51##
NZ33, available from Kenrich, Inc., Bayonne, N.J., of the formula
##STR52##
KR 39DS, available from Kenrich, Inc., Bayonne, N.J., of the
formula ##STR53##
LICA97, available from Kenrich, Inc., Bayonne, N.J., of the formula
##STR54##
and Z6030, available from Dow Chemical Co., Midland, Mich., of the
formula ##STR55##
The adhesion promoter typically is admixed with a solvent and
coated onto the article for which bonding is desired. Examples of
suitable solvents include water (particularly acidified water,
acidified with an acid such as glacial acetic acid to a pH of from
about 3.5 to about 4.5), methanol, isopropanol, 2-methoxyethanol,
glycol based solvents such as butyl carbitol, 2-methoxyethyl ether,
cellosolve, cellosolve acetate, methyl cellosolve, ethyl
cellosolve, methyl ethyl ketone, xylene, N-methyl pyrrolidone, and
the like, as well as mixtures thereof. Silane adhesion promoters
are typically applied from aqueous solvents, since hydrolysis of
the alkoxy, aryloxy, or arylalkyloxy groups to reactive groups on
the surface of the coated article is desired. This result is best
effected by reaction with water prior to spin casting, although
trialkoxy containing silanes or partially hydrolyzed silanes may be
directly applied to the article to be coated. The adhesion promoter
is present in the solvent in any desired or effective amount,
typically from about 0.005 to about 10 percent by weight, and
preferably from about 0.1 to about 1 percent by weight of the
solution, although the amount can be outside of this range. Coating
of the article or articles to be bonded can be by any desired or
suitable method, such as spin casting or the like. After coating
the article to be bonded, heat treatment of the silane adhesion
promoter is typically carried out to effect the hydrolysis reaction
of the silanol groups with surface hydroxyls. Typically, the
zirconate and titanate adhesion promoters are already in the
surface reactive form and can be applied directly from solvent.
Heat activation is also not necessary with zirconate and titanate
adhesion promoters, and in situations wherein the adhesion promoter
has many photoactive groups, heat treatment can result in premature
crosslinking within the adhesion promoter layer prior to contacting
the article to be bonded. When spin casting methods are used, the
spin rate and solution concentrations are adjusted to produce an
adhesion promoter layer of the desired thickness. Typical adhesion
promoter layer thicknesses range from as low as a monolayer (less
than about 10 to about 100 nanometers) to many multilayers (about
0.5 to about 5.0 microns). Spin rates typically range from about
300 to about 3,000 rpm, and preferably from about 1,500 to about
2,000 rpm, although the rate can be outside of these ranges. After
applying the silane adhesion promoter layer, the adhesion promoter
typically is heat activated for from about 5 to about 15 minutes,
typically at temperatures of from about 50 to about 100.degree. C.,
to effect the bonding between the silane and the article to be
bonded.
In another embodiment of the present invention, the adhesion
promoter is added directly to a solution containing the polymer
with photosensitivity-imparting substituents. In this instance, the
optimum concentration of adhesion promoter in the solution can be
determined by the mole fraction of the photoactive groups.
Typically the adhesion promoter concentration in the polymer
solution is in from about 1 to about 5 mole excess of the
photoactive groups on the backbone of the photopatternable polymer
monomers.
Specific embodiments of the invention will now be described in
detail. These examples are intended to be illustrative, and the
invention is not limited to the materials, conditions, or process
parameters set forth in these embodiments. All parts and
percentages are by weight unless otherwise indicated.
EXAMPLE I
Adhesion promoter solutions were prepared by admixing LICA97
adhesion promoter (obtained from Kenrich; commercially obtained
stock solution contained 55 percent by weight of the adhesion
promoter in a solvent) and 2-methoxyethanol to form solutions
containing 0.05 percent by weight of the stock solution, 0.20
percent by weight of the stock solution, and 0.33 percent by weight
of the stock solution.
Phosphosilicate glass wafers were first washed to remove any
phosphate salts that may have leached out of the glass and
segregated on the surface. Thereafter, the adhesion promoter
solution thus prepared was spin coated onto the wafer at 2,000 rpm
for 30 seconds, followed by air drying for 10 minutes. A solution
was then prepared containing N-methyl pyrrolidone and a polymer of
the formula ##STR56##
wherein the polymer had about 1.25 chloromethyl groups per repeat
monomer unit and about 0.75 acryloyl group per repeat monomer unit
and had a weight average molecular weight of about 43,700, with the
polymer present in the solution in an amount of about 20 percent by
weight. The polymer solution also contained a methyl ether of
hydroquinone (MEHQ) inhibitor in an amount of about 500 parts per
million. A small amount of a 0.2 weight percent solution of an
initiator (Michler's ketone, 4,4'-bis-dimethylaminobenzophenone)
was added just prior to spin casting. The polymer solution spin
cast onto the adhesion promoter at 500 rpm for 30 seconds, followed
by a pre-exposure bake in an oven at 80.degree. C. for 15 minutes
to drive off the N-methyl pyrrolidone. Thereafter, the wafer was
flood exposed to ultraviolet light for 64 seconds using a Canon
mask aligner. Post-exposure bake was in an oven which was heated to
120.degree. C. at a rate of 2.degree. C. per minute, maintained at
that temperature for 2 hours, further heated to 250.degree. C. at
2.degree. C. per minute, and maintained at 250.degree. C. for 2
hours. The resulting wafer had a layer of the polymer about 4
microns thick.
The wafers were diced into 3 millimeter by 5 millimeter samples,
and polymer film adhesion was qualitatively measured using a tape
test. The samples were first tested for initial adhesion retention
before soaking in various liquids. After soaking for a given period
of time, the sample was removed from the liquid, rinsed with water,
and blow dried. The samples were then taped to an aluminum block
using double-sided adhesive tape, with two pieces applied in the
shape of a cross over each sample. The tape was then swiftly pulled
off the sample and the sample and tape were inspected for any signs
of polymer film peeling. The test was terminated when 50 percent or
more of the polymer film had delaminated from the phosphosilicate
glass substrate.
Samples were soaked at 25.degree. C. in aqueous solutions of
imidazole (20 percent by weight imidazole), urea (20 percent by
weight urea), and N,N'-bis(3-aminopropyl)-1,2-ethylenediamine
(N-BAPED) (5 percent by weight N-BAPED). The time to 50 percent or
more delamination for samples coated with the adhesion promoter
from solutions containing the three different concentrations was as
follows:
0.05% 0.20% 0.33% imidazole 15-16 weeks 2-3 days 4 days urea 14-15
weeks 5-23 hours <16 hours N-BAPED 2-3 weeks 1.5-3 hours <16
hours
The sample made with the 0.05% adhesion promoter solution was also
soak tested at 40.degree. C. The time to 50 percent or more
delamination for this sample was 9.5 to 13.5 days in imidazole, 7.5
to 9 days in urea, and 3.5 to 5 days in N-BAPED.
EXAMPLE II
Adhesion promoter solutions were prepared by admixing NZ39 adhesion
promoter (obtained from Kenrich; commercially obtained product
contained 100 percent by weight of the adhesion promoter) and
isopropanol to form solutions containing 0.43 percent by weight of
the adhesion promoter, 0.59 percent by weight of the adhesion
promoter, 1.02 percent by weight of the adhesion promoter, and 1.42
percent by weight of the adhesion promoter.
The adhesion promoter solutions were coated onto wafers by the
method described in Example I, followed by coating the polymer
containing photosensitivity-imparting substituents onto the
adhesion promoter and soak testing by the methods described in
Example I. The time to 50 percent or more delamination for samples
coated with the adhesion promoter from solutions containing the
four different concentrations was as follows:
0.43% 0.59% 1.02% 1.42% imidazole <1 second* <1 second* 15-17
weeks >7 weeks** urea <1 second* <1 second* 15-17 weeks
5-6 weeks N-BAPED <1 second* <1 second* 4-6 days 3-5 days
*failed prior to soak **test terminated after 7 weeks without
having reached failure
The samples made with the 1.02% adhesion promoter solution and the
1.42% adhesion promoter solution were also soak tested at
40.degree. C. The time to 50 percent or more delamination for these
samples was as follows:
1.02% 1.42% imidazole 13-14 days 8-10 days urea 2-4 days 2-4 days
N-BAPED 3.5-5 days 2.5-4.5 days
EXAMPLE III
Adhesion promoter solutions were prepared by admixing KR 39DS
adhesion promoter (obtained from Kendch; commercially obtained
product contained 100 percent by weight of the adhesion promoter)
and a solvent to form a solution containing 0.21 percent by weight
of the adhesion promoter in butyl carbitol and a solution
containing 1.15 percent by weight of the adhesion promoter in ethyl
cellosolve.
The adhesion promoter solutions were coated onto wafers by the
method described in Example I, followed by coating the polymer
containing photosensitivity-imparting substituents onto the
adhesion promoter and soak testing by the methods described in
Example I. The time to 50 percent or more delamination for samples
coated with the adhesion promoter from solutions containing the two
different concentrations was as follows:
0.21%. 1.15% imidazole <1 second* >6 weeks** urea <1
second* >6 weeks** N-BAPED <1 second* 4-6 days *failed prior
to soak **test terminated after 6 weeks without having reached
failure
The sample made with the 1.15% adhesion promoter solution was also
soak tested at 40.degree. C. The time to 50 percent or more
delamination for this sample was 12 to 14 days in imidazole, 10 to
13 days in urea, and 2 to 16 hours in N-BAPED.
EXAMPLE IV
Adhesion promoter solutions were prepared by admixing NZ33 adhesion
promoter (obtained from Kenrich; commercially obtained stock
solution contained 47 percent by weight of the adhesion promoter in
a solvent) and xylene to form solutions containing 1.15 percent by
weight of the stock solution and 1.40 percent by weight of the
stock solution.
The adhesion promoter solutions were coated onto wafers by the
method described in Example I, followed by coating the polymer
containing photosensitivity-imparting substituents onto the
adhesion promoter and soak testing by the methods described in
Example I. In each instance, the samples failed prior to soak. It
is believed that because the commercial stock solution contained
only 47 percent by weight of the adhesion promoter, coating
solutions of this adhesion promoter should contain at least about 2
percent by weight of the stock solution to achieve good
results.
EXAMPLE V
Adhesion promoter solutions were prepared by admixing Z6030
adhesion promoter (obtained from Dow Chemical; commercially
obtained stock solution contained 99 percent by weight of the
adhesion promoter) and acidified water (acidified by adding glacial
acetic acid to distilled water until the pH was from about 3.5 to
about 4.5) to form solutions containing 0.30 percent by weight of
the stock solution and 1.00 percent by weight of the stock
solution.
The adhesion promoter solutions were coated onto wafers by the
method described in Example I, followed by coating the polymer
containing photosensitivity-imparting substituents onto the
adhesion promoter and soak testing by the methods described in
Example I, with the exception that subsequent to spin coating the
adhesion promoter onto the wafer, the wafer was heated in an oven
at 80.degree. C. for 10 minutes (instead of being air dried for 10
minutes) to effect the alkoxy/silanol condensation reaction. The
time to 50 percent or more delamination for samples coated with the
adhesion promoter from solutions containing the two different
concentrations was as follows:
0.30% 1.00% imidazole 21-23 weeks 2-3 days urea >29 weeks* 23
days N-BAPED >29 weeks* 1-3 days *test terminated after 29 weeks
without having reached failure
The sample made with the 0.30% adhesion promoter solution was also
soak tested at 40.degree. C. The time to 50 percent or more
delamination for this sample was 7 to 10 days in imidazole, 16 to
22 days in urea, and 10 to 15 days in N-BAPED.
COMPARATIVE EXAMPLE A
A wafer was coated directly with a polymer containing
photosensitivity-imparting groups by the method described in
Example I, with no adhesion promoter being used. The resulting
wafers were cut into samples and soak tested by the method
described in Example I. The time to 50 percent or more delamination
for the samples was 1 to 2 hours in imidazole, 1 to 1.5 hours in
urea, and 15 to 17 minutes in N-BAPED.
COMPARATIVE EXAMPLE B
An adhesion promoter solution was prepared by admixing 5 drops of
Z6020 adhesion promoter (of the formula ##STR57##
obtained from Dow Chemical; commercially obtained product contained
100 percent by weight of the adhesion promoter), 1 drop of water,
and 100 milliliters of methanol.
The adhesion promoter solutions were coated onto wafers by the
method described in Example V, followed by coating the polymer
containing photosensitivity-imparting substituents onto the
adhesion promoter and soak testing by the methods described in
Example I. The time to 50 percent or more delamination for the
samples was 1 to 3 hours in imidazole, 17 to 36 minutes in urea,
and 18 to 37 minutes in N-BAPED.
POLYMER SYNTHESIS EXAMPLE I
A polyarylene ether ketone of the formula ##STR58##
wherein n is between about 6 and about 30 (hereinafter referred to
as poly(4-CPK-BPA)) was prepared as follows. A 1 liter, 3-neck
round-bottom flask equipped with a Dean-Stark (Barrett) trap,
condenser, mechanical stirrer, argon inlet, and stopper was
situated in a silicone oil bath. 4,4'-Dichlorobenzophenone (Aldrich
11,370, Aldrich Chemical Co., Milwaukee, Wis., 50 grams),
bis-phenol A (Aldrich 23,965-8, 48.96 grams), potassium carbonate
(65.56 grams), anhydrous N,N-dimethylacetamide (300 milliliters),
and toluene (55 milliliters) were added to the flask and heated to
175.degree. C. (oil bath temperature) while the volatile toluene
component was collected and removed. After 24 hours of heating at
175.degree. C. with continuous stirring, an aliquot of the reaction
product that had been precipitated into methanol was analyzed by
gel permeation chromatography (gpc) (elution solvent was
tetrahydrofuran) with the following results: M.sub.n 4464,
M.sub.peak 7583, M.sub.w 7927, M.sub.z 12,331, and M.sub.z+1
16,980. After 48 hours at 175.degree. C. with continuous stirring,
the reaction mixture was filtered to remove potassium carbonate and
precipitated into methanol (2 gallons). The polymer
(poly(4-CPK-BPA)) was isolated in 86% yield after filtration and
drying in vacuo. GPC analysis was as follows: M.sub.n 5347,
M.sub.peak 16,126, M.sub.w 15,596, M.sub.z 29,209, and M.sub.z+1
42,710. The glass transition temperature of the polymer was about
120.+-.10.degree. C. as determined using differential scanning
calorimetry at a heating rate of 20.degree. C. per minute. As a
result of the stoichiometries used in the reaction, it is believed
that this polymer had end groups derived from bis-phenol A.
POLYMER SYNTHESIS EXAMPLE II
A polyarylene ether ketone of the formula ##STR59##
wherein n is between about 2 and about 30 (hereinafter referred to
as poly(4-CPK-BPA)) was prepared as follows. A 5 liter, 3-neck
round-bottom flask equipped with a Dean-Stark (Barrett) trap,
condenser, mechanical stirrer, argon inlet, and stopper was
situated in a silicone oil bath. 4,4'-Dichlorobenzophenone (Aldrich
11,370, Aldrich Chemical Co., Milwaukee, Wis., 250 grams),
bis-phenol A (Aldrich 23,965-8, 244.8 grams), potassium carbonate
(327.8 grams), anhydrous N,N-dimethylacetamide (1,500 milliliters),
and toluene (275 milliliters) were added to the flask and heated to
175.degree. C. (oil bath temperature) while the volatile toluene
component was collected and removed. After 48 hours of heating at
175.degree. C. with continuous stirring, the reaction mixture was
filtered to remove insoluble salts, and the resultant solution was
added to methanol (5 gallons) to precipitate the polymer. The
polymer was isolated by filtration, and the wet filter cake was
washed with water (3 gallons) and then with methanol (3 gallons).
The yield was 360 grams of vacuum dried product. The molecular
weight of the polymer was determined by gel permeation
chromatography (gpc) (elution solvent was tetrahydrofuran) with the
following results: M.sub.n 3,601, M.sub.peak 5,377, M.sub.w 4,311,
M.sub.z 8,702, and M.sub.z+1 12,951. The glass transition
temperature of the polymer was between 125 and 155.degree. C. as
determined using differential scanning calorimetry at a heating
rate of 20.degree. C. per minute dependent on molecular weight. As
a result of the stoichiometries used in the reaction, it is
believed that this polymer had end groups derived from bis-phenol
A.
POLYMER SYNTHESIS EXAMPLE III
Poly(4-CPK-BPA) prepared as described in Polymer Synthesis Example
I (10 grams) in 1,1,2,2-tetrachloroethane (100 milliliters, 161.9
grams), paraformaldehyde (5 grams), p-toluene-sulfonic acid
monohydrate (1 gram), acrylic acid (15.8 grams), and crushed
4-methoxy-phenol (MEHQ, 0.2 gram) were charged in a 6.5 fluid ounce
beverage bottle equipped with a magnetic stirrer. The bottle was
stoppered with a rubber septum and was then heated to 105.degree.
C. in a silicone oil bath under argon using a needle inlet. The
argon needle inlet was removed when the oil bath achieved
90.degree. C. Heating at 105.degree. C. was continued with constant
magnetic stirring for 1.5 hours. More MEHQ (0.2 grams) in 1
milliliter of 1,1,2,2-tetrachloroethane was then added by syringe,
and heating at 105.degree. C. with stirring was continued for 1.5
hours longer. The reaction mixture was initially a cloudy
suspension which become clear on heating. The reaction vessel was
immersed as much as possible in the hot oil bath to prevent
condensation of paraformaldehyde onto cooler surfaces of the
reaction vessel. The reaction mixture was allowed to return to
25.degree. C. and was then filtered through a 25 to 50 micron
sintered glass Buchner funnel. The reaction solution was added to
methanol (1 gallon) to precipitate the polymer designated
poly(acryloylmethyl-4-CPK-BPA), of the formula ##STR60##
wherein n is between about 6 and about 50. .sup.1 H NMR
spectrometry was used to identify approximately 1 acryloylmethyl
group for every four monomer (4-CPK-BPA) repeat units (i.e., a
degree of acryloylation of 0.25). The
poly(acryloylmethyl-4-CPK-BPA) was then dissolved in methylene
chloride and reprecipitated into methanol (1 gallon) to yield 10
grams of fluffy white solid.
POLYMER SYNTHESIS EXAMPLE IV
A solution of chloromethyl ether in methyl acetate was made by
adding 282.68 grams (256 milliliters) of acetyl chloride to a
mixture of dimethoxy methane (313.6 grams, 366.8 milliliters) and
methanol (10 milliliters) in a 5 liter 3-neck round-bottom flask
equipped with a mechanical stirrer, argon inlet, reflux condenser,
and addition funnel. The solution was diluted with 1,066.8
milliliters of 1,1,2,2-tetrachloroethane and then tin tetrachloride
(2.4 milliliters) was added via a gas-tight syringe along with
1,1,2,2-tetrachloroethane (133.2 milliliters) using an addition
funnel. The reaction solution was heated to 500.degree. C.
Thereafter, a solution of poly(4-CPK-BPA) prepared as described in
Polymer Synthesis Example II (160.8 grams) in 1,000 milliliters of
tetrachloroethane was added rapidly. The reaction mixture was then
heated to reflux with an oil bath set at 110.degree. C. After four
hours reflux with continuous stirring, heating was discontinued and
the mixture was allowed to cool to 25.degree. C. The reaction
mixture was transferred in stages to a 2 liter round bottom flask
and concentrated using a rotary evaporator with gentle heating up
to 50.degree. C. while reduced pressure was maintained with a
vacuum pump trapped with liquid nitrogen. The concentrate was added
to methanol (4 gallons) to precipitate the polymer using a Waring
blender. The polymer was isolated by filtration and vacuum dried to
yield 200 grams of poly(4-CPK-BPA) with 1.5 chloromethyl groups per
repeat unit as identified using .sup.1 H NMR spectroscopy. When the
same reaction was carried out for 1, 2, 3, and 4 hours, the amount
of chloromethyl groups per repeat unit was 0.76, 1.09, 1.294, and
1.496, respectively.
Solvent free polymer was obtained by reprecipitation of the polymer
(75 grams) in methylene chloride (500 grams) into methanol (3
gallons) followed by filtration and vacuum drying to yield 70.5
grams (99.6% theoretical yield) of solvent free polymer.
When the reaction was carried out under similar conditions except
that 80.4 grams of poly(4-CPK-BPA) was used instead of 160.8 grams
and the amounts of the other reagents were the same as indicated
above, the polymer is formed with 1.31, 1.50, 1.75, and 2
chloromethyl groups per repeat unit in 1, 2, 3, and 4 hours,
respectively, at 110.degree. C. (oil bath temperature).
When 241.2 grams of poly(4-CPK-BPA) was used instead of 160.8 grams
with the other reagents fixed, poly(CPK-BPA) was formed with 0.79,
0.90, 0.98, 1.06, 1.22, and 1.38 chloromethyl groups per repeat
unit in 1, 2, 3, 4, 5, and 6 hours, respectively, at 110.degree. C.
(oil bath temperature).
When 321.6 grams of poly(4-CPK-BPA) was used instead of 160.8 grams
with the other reagents fixed, poly(CPK-BPA) was formed with 0.53,
0.59, 0.64, 0.67, 0.77, 0.86, 0.90, and 0.97 chloromethyl groups
per repeat unit in 1, 2, 3, 4, 5, 6, 7, and 8 hours, respectively,
at 110.degree. C. (oil both temperature).
POLYMER SYNTHESIS EXAMPLE V
A polyarylene ether ketone of the formula ##STR61##
was prepared as described in Polymer Synthesis Example I. A
solution of chloromethyl ether in methyl acetate was made by adding
35.3 grams of acetyl chloride to a mixture of dimethoxy methane (45
milliliters) and methanol (1.25 milliliters) in a 500 milliliter
3-neck round-bottom flask equipped with a mechanical stirrer, argon
inlet, reflux condenser, and addition funnel. The solution was
diluted with 150 milliliters of 1,1,2,2-tetrachloroethane and then
tin tetrachloride (0.3 milliliters) was added via syringe. The
solution was heated to reflux with an oil bath set at 110.degree.
C. Thereafter, a solution of poly(4-CPK-BPA) (10 grams) in 125
milliliters of 1,1,2,2-tetrachloroethane was added over 8 minutes.
After two hours reflux with continuous stirring, heating was
discontinued and the mixture was allowed to cool to 25.degree. C.
The reaction mixture was transferred to a rotary evaporator with
gentle heating at between 50 and 55.degree. C. After 1 hour, when
most of the volatiles had been removed, the reaction mixture was
added to methanol (each 25 milliliters of solution was added to
0.75 liter of methanol) to precipitate the polymer using a Waring
blender. The precipitated polymer was collected by filtration,
washed with methanol, and air-dried to yield 13 grams of off-white
powder. The polymer had about 1.5 CH.sub.2 Cl groups per repeat
unit.
POLYMER SYNTHESIS EXAMPLE VI
A solution was prepared containing 90 grams of a chloromethylated
polymer prepared as described in Polymer Synthesis Example IV with
1.5 chloromethyl groups per repeat unit in 639 milliliters (558.5
grams) of N,N-dimethylacetamide and the solution was magnetically
stirred at 25.degree. C. with sodium acrylate (51.39 grams) for 1
week. The reaction mixture was then centrifuged, and the supernate
was added to methanol (4.8 gallons) using a Waring blender in
relative amounts of 25 milliliters of polymer solution per 0.75
liter of methanol. The white powder that precipitated was filtered,
and the wet filter cake was washed with water (3 gallons) and then
methanol (3 gallons). The polymer was then isolated by filtration
and vacuum dried to yield 73.3 grams of a white powder. The polymer
had 3 acrylate groups for every 4 repeating monomer units and 3
chloromethyl groups for every 4 repeating monomer units and a
weight average molecular weight of about 25,000.
When the reaction was repeated with poly(4-CPK-BPA) with 2
chloromethyl groups per repeat unit and the other reagents remained
the same, the reaction took four days to achieve 0.76 acrylate
groups per repeat unit and 1.24 chloromethyl groups per repeat
unit.
When the reaction was repeated with poly(4-CPK-BPA) with 1.0
chloromethyl groups per repeat unit and the other reagents remained
the same, the reaction took 14-days to achieve 0.75 acrylate groups
per repeat unit and 2.5 chloromethyl groups per repeat unit.
POLYMER SYNTHESIS EXAMPLE VII
A chloromethylated polyarylene ether ketone having 1.5 chloromethyl
groups per repeat unit was prepared as described in Polymer
Synthesis Example IV. A solution containing 10 grams of the
chloromethylated polymer in 71 milliliters of N,N-dimethyl
acetamide was magnetically stirred with 5.71 grams of sodium
acetate (obtained from Aldrich Chemical Co., Milwaukee, WI). The
reaction was allowed to proceed for one week. The reaction mixture
was then centrifuged and the supernate was added to methanol (0.5
gallon) to precipitate the polymer. The polymer was then filtered,
washed with water (2 liters), and subsequently washed with methanol
(0.5 gallon). Approximately half of the chloromethyl groups were
replaced with methylcarboxymethylene groups, and it is believed
that the polymer was of the formula ##STR62##
When the process was repeated under similar conditions but allowed
to proceed for about 2 weeks, nearly all of the chloromethyl groups
were replaced with methylcarboxymethylene groups, and the resulting
polymer was believed to be of the formula ##STR63##
POLYMER SYNTHESIS EXAMPLE VIII
The process of Polymer Synthesis Example VII was repeated except
that the 5.71 grams of sodium acetate were replaced with 5.71 grams
of sodium methoxide (obtained from Aldrich Chemical Co., Milwaukee,
Wis.). After about two hours, approximately half of the chlorine
atoms on the chloromethyl groups were replaced with methoxy groups,
and it is believed that the polymer was of the formula
##STR64##
When the process was repeated under similar conditions but allowed
to proceed for about 2 weeks, nearly all of the chlorine atoms on
the chloromethyl groups were replaced with methoxy groups, and the
resulting polymer was believed to be of the formula ##STR65##
POLYMER SYNTHESIS EXAMPLE IX
A chloromethylated polyarylene ether ketone was prepared as
described in Polymer Synthesis Example V. A solution was then
prepared containing 11 grams of the chloromethylated polymer in 100
milliliters (87.4 grams) of N,N-dimethylacetamide and the solution
was magnetically stirred at 25.degree. C. with sodium acrylate (30
grams) for 1 week. The reaction mixture was then filtered and added
to methanol using a Waring blender in relative amounts of 25
milliliters of polymer solution per 0.75 liter of methanol. The
white powder that precipitated was reprecipitated into methanol
from a 20 weight percent solids solution in methylene chloride and
was them air dried to yield 7.73 grams of a white powder. The
polymer had 3 acrylate groups for every 4 repeating monomer units
and 3 chloromethyl groups for every 4 repeating monomer units.
POLYMER SYNTHESIS EXAMPLE X
A polyarylene ether ketone of the formula ##STR66##
wherein n is between about 6 and about 30 (hereinafter referred to
as poly(4-CPK-BPA)) was prepared as follows. A 1 liter, 3-neck
round-bottom flask equipped with a Dean-Stark (Barrett) trap,
condenser, mechanical stirrer, argon inlet, and stopper was
situated in a silicone oil bath. 4,4'-Dichlorobenzophenone (Aldrich
11,370, Aldrich Chemical Co., Milwaukee, Wis., 53.90 grams),
bis-phenol A (Aldrich 23,965-8, 45.42 grams), potassium carbonate
(65.56 grams), anhydrous N,N-dimethylacetamide (300 milliliters),
and toluene (55 milliliters) were added to the flask and heated to
175.degree. C. (oil bath temperature) while the volatile toluene
component was collected and removed. After 24 hours of heating at
175.degree. C. with continuous stirring, the reaction mixture was
filtered to remove potassium carbonate and precipitated into
methanol (2 gallons). The polymer (poly(4-CPK-BPA)) was isolated in
86% yield after filtration and drying in vocuo. GPC analysis was as
follows: M.sub.n 4,239, M.sub.peak 9,164, M.sub.w 10,238, M.sub.z
18,195, and M.sub.z+1 25,916. Solution cast films from methylene
chloride were clear, tough, and flexible. As a result of the
stoichiometries used in the reaction, it is believed that this
polymer had end groups derived from 4,4-dichlorobenzophenone.
POLYMER SYNTHESIS EXAMPLE XI
A benzophenone-terminated polyarylene ether ketone prepared as
described in Polymer Synthesis Example X was 15 chloromethyl
substituted as described in Polymer Synthesis Example IV, resulting
in a benzophenone-terminated, chloromethylated polymer having 0.5
chloromethyl groups per repeat unit.
A solution was prepared containing the benzophenone-terminated
chloromethylated polyarylene ether ketone thus prepared in
N-methylpyrrolidinone at a concentration of 33.7 percent by weight
polymer solids. To this solution was added N,N-dimethyl ethyl
methacrylate (obtained from Aldrich Chemical Co., Milwaukee, Wis.)
in an amount of 6.21 percent by weight of the polymer solution, and
the resulting solution was stirred for 2 hours. The reaction of the
chloromethyl groups with the N,N-dimethyl ethyl methocrylate
occurred quickly, resulting in formation of a polymer having about
0.5 N,N-dimethyl ethyl methacrylate groups per monomer repeat
unit.
POLYMER SYNTHESIS EXAMPLE XII
Fifty grams of a polymer having 0.75 acrylate groups per repeat
unit and 0.75 chloromethyl groups per repeat unit prepared as
described in Polymer Synthesis Example VI is dissolved in 117
milliliters of N,N-dimethylacetamide and magnetically stirred at
5.degree. C. in an ice bath with 30 milliliters of trimethylamine.
The reaction mixture is allowed to return to 25.degree. C. over two
hours and stirring is continued for an additional two hours. The
unreacted trimethylamine is then removed using a rotary evaporator
and the resulting polymer has both acrylate substituents and
trimethylammonium chloride substituents.
POLYMER SYNTHESIS EXAMPLE XIII
A polymer of the formula ##STR67##
wherein n represents the number of repeating monomer units was
prepared as follows. A 500 milliliter, 3-neck round-bottom flask
equipped with a Dean-Stark (Barrett) trap, condenser, mechanical
stirrer, argon inlet, and stopper was situated in a silicone oil
bath. 4,4'-Dichlorobenzophenone (Aldrich 11,370, Aldrich Chemical
Co., Milwaukee, Wis., 16.32 grams, 0.065 mol),
bis(4-hydroxyphenyl)methane (Aldrich, 14.02 grams, 0.07 mol),
potassium carbonate (21.41 grams), anhydrous N,N-dimethylacetamide
(100 milliliters), and toluene (100 milliliters) were added to the
flask and heated to 175.degree. C. (oil bath temperature) while the
volatile toluene component was collected and removed. After 48
hours of heating at 175.degree. C. with continuous stirring, the
reaction mixture was filtered and added to methanol to precipitate
the polymer, which was collected by filtration, washed with water,
and then washed with methanol. The yield of vacuum dried product,
poly(4-CPK-BPM), was 24 grams. The polymer dissolved on heating in
N-methylpyrrolidinone, N,N-dimethylacetamide, and
1,1,2,2-tetrachloroethane. The polymer remained soluble after the
solution had cooled to 25.degree. C.
POLYMER SYNTHESIS EXAMPLE XIV
The polymer poly(4-CPK-BPM), prepared as described in Polymer
Synthesis Example XIII, was acryloylated with paraformaldehyde by
the process described in Polymer Synthesis Example II. Similar
results were obtained.
POLYMER SYNTHESIS EXAMPLE XV
The polymer poly(4-CPK-BPM), prepared as described in Polymer
Synthesis Example XIII, was chloromethylated as follows. A solution
of chloromethyl methyl ether (6 mmol/milliliter) in methyl acetate
was prepared by adding acetyl chloride (35.3 grams) to a mixture of
dimethoxymethane (45 milliliters) and methanol (1.25 milliliters).
The solution was diluted with 150 milliliters of
1,1,2,2-tetrachloroethane and then tin tetrachloride (0.3
milliliters) was added. After taking the mixture to reflux using an
oil bath set at 110.degree. C., a solution of poly(4-CPK-BPM) (10
grams) in 125 milliliters of 1,1,2,2-tetrachloroethane was added.
Reflux was maintained for 2 hours and then 5 milliliters of
methanol were added to quench the reaction. The reaction solution
was added to 1 gallon of methanol using a Waring blender to
precipitate the product, chloromethylated poly(4-CPK-BPM), which
was collected by filtration and vacuum dried. The yield was 9.46
grams of poly(4-CPK-BPM) with 2 chloromethyl groups per polymer
repeat unit. The polymer had the following structure: ##STR68##
POLYMER SYNTHESIS EXAMPLE XVI
Poly(4-CPK-BPM) with 2 chloromethyl groups per repeat unit (1 gram,
prepared as described in Polymer Synthesis Example XV) in 20
milliliters of N,N-dimethylacetamide was magnetically stirred with
sodium acrylate for 112 hours at 25.degree. C. The solution was
added to methanol using a Waring blender to precipitate the
polymer, which was filtered and vacuum dried. Between 58 and 69
percent of the chloromethyl groups had been replaced with acryloyl
groups. The product had the following formula: ##STR69##
POLYMER SYNTHESIS EXAMPLE XVII
A polymer of the formula ##STR70##
prepared as follows. A 500 milliliter, 3-neck round-bottom flask
equipped with a Dean-Stark (Barrett) trap, condenser, mechanical
stirrer, argon inlet, and stopper was situated in a silicone oil
bath. 4,4'-Dichlorobenzophenone (Aldrich 11,370, Aldrich Chemical
Co., Milwaukee, Wis., 16.32 grams, 0.065 mol), hexafluorobisphenol
A (Aldrich, 23.52 grams, 0.07 mol), potassium carbonate (21.41
grams), anhydrous N,N-dimethylacetamide (100 milliliters), and
toluene (100 milliliters) were added to the flask and heated to
175.degree. C. (oil bath temperature) while the volatile toluene
component was collected and removed. After 48 hours of heating at
175.degree. C. with continuous stirring, the reaction mixture was
filtered and added to methanol to precipitate the polymer, which
was collected by filtration, washed with water, and then washed
with methanol. The yield of vacuum dried product,
poly(4-CPK-HFBPA), was 20 grams. The polymer was analyzed by gel
permeation chromatography (gpc) (elution solvent was
tetrahydrofuran) with the following results: M.sub.n 1,975,
M.sub.peak 2,281, M.sub.w 3,588, and M.sub.z+1 8,918.
POLYMER SYNTHESIS EXAMPLE XVIII
The polymer poly(4-CPK-HFBPA), prepared as described in Polymer
Synthesis Example XVII, was acryloylated with paraformaldehyde by
the process described in Polymer Synthesis Example II. Similar
results were obtained.
POLYMER SYNTHESIS EXAMPLE XIX
The polymer poly(4-CPK-HFBPA), prepared as described in Polymer
Synthesis Example XVII, is chloromethylated by the process
described in Polymer Synthesis Example XV. It is believed that
similar results will be obtained.
POLYMER SYNTHESIS EXAMPLE XX
The chloromethylated polymer poly(4-CPK-HFBPA), prepared as
described in Polymer Synthesis Example XIX, is acryloylated by the
process described in Polymer Synthesis Example XVI. It is believed
that similar results will be obtained.
POLYMER SYNTHESIS EXAMPLE XXI
A polymer of the formula ##STR71##
wherein n represents the number of repeating monomer units was
prepared as follows. A 1-liter, 3-neck round-bottom flask equipped
with a Dean-Stark (Barrett) trap, condenser, mechanical stirrer,
argon inlet, and stopper was situated in a silicone oil bath.
4,4'-Difluorobenzophenone (Aldrich Chemical Co., Milwaukee, Wis.,
43.47 grams, 0.1992 mol), 9,9'-bis(4-hydroxyphenyl)fluorenone (Ken
Seika, Rumson, N.J., 75.06 grams, 0.2145 mol), potassium carbonate
(65.56 grams), anhydrous N,N-dimethylacetamide (300 milliliters),
and toluene (52 milliliters) were added to the flask and heated to
175.degree. C. (oil bath temperature) while the volatile toluene
component was collected and removed. After 5 hours of heating at
175.degree. C. with continuous stirring, the reaction mixture was
allowed to cool to 25.degree. C. The solidified mass was treated
with acetic acid (vinegar) and extracted with methylene chloride,
filtered, and added to methanol to precipitate the polymer, which
was collected by filtration, washed with water, and then washed
with methanol. The yield of vacuum dried product, poly(4-FPK-FBPA),
was 71.7 grams. The polymer was analyzed by gel permeation
chromatography (gpc) (elution solvent was tetrahydrofuran) with the
following results: M.sub.n 59,100, M.sub.peak 144,000, M.sub.w
136,100, M.sub.z 211,350, and M.sub.z+1 286,100.
POLYMER SYNTHESIS EXAMPLE XXII
A polymer of the formula ##STR72##
wherein n represents the number of repeating monomer units was
prepared as follows. A 1-liter, 3-neck round-bottom flask equipped
with a Dean-Stark (Barrett) trap, condenser, mechanical stirrer,
argon inlet, and stopper was situated in a silicone oil bath.
4,4'-Dichlorobenzophenone (Aldrich Chemical Co., Milwaukee, Wis.,
50.02 grams, 0.1992 mol), 9,9'-bis(4-hydroxyphenyl)fluorenone (Ken
Seika, Rumson, N.J., 75.04 grams, 0.2145 mol), potassium carbonate
(65.56 grams), anhydrous N,N-dimethylacetamide (300 milliliters),
and toluene (52 milliliters) were added to the flask and heated to
175.degree. C. (oil bath temperature) while the volatile toluene
component was collected and removed. After 24 hours of heating at
175.degree. C. with continuous stirring, the reaction mixture was
allowed to cool to 25.degree. C. The reaction mixture was filtered
and added to methanol to precipitate the polymer, which was
collected by filtration, washed with water, and then washed with
methanol. The yield of vacuum dried product, poly(4-CPK-FBP), was
60 grams.
POLYMER SYNTHESIS EXAMPLE XXIII
The polymer poly(4-CPK-FBP), prepared as described in Polymer
Synthesis Example XXII, was chloromethylated as follows. A solution
of chloromethyl methyl ether (6 mmol/milliliter) in methyl acetate
was prepared by adding acetyl chloride (38.8 grams) to a mixture of
dimethoxymethane (45 milliliters) and methanol (1.25 milliliters).
The solution was diluted with 100 milliliters of
1,1,2,2-tetrachloroethane and then tin tetrachloride (0.5
milliliters) was added in 50 milliliters of
1,1,2,2-tetrachloroethane. After taking the mixture to reflux using
an oil bath set at 100.degree. C., a solution of poly(4-CPK-FBP)
(10 grams) in 125 milliliters of 1,1,2,2-tetrachloroethane was
added. The reaction temperature was maintained at 100.degree. C.
for 1 hour and then 5 milliliters of methanol were added to quench
the reaction. The reaction solution was added to 1 gallon of
methanol using a Waring blender to precipitate the product,
chloromethylated poly(4-CPK-FBP), which was collected by filtration
and vacuum dried. The yield was 9.5 grams of poly(4-CPK-FBP) with
1.5 chloromethyl groups per polymer repeat unit. When the reaction
was carried out at 110.degree. C. (oil bath set temperature), the
polymer gelled within 80 minutes. The polymer had the following
structure: ##STR73##
POLYMER SYNTHESIS EXAMPLE XXIV
Poly(4-CPK-FBP) with 1.5 chloromethyl groups per repeat unit (1
gram, prepared as described in Polymer Synthesis Example XXIII) in
20 milliliters of N,N-dimethylacetamide was magnetically stirred
with sodium acrylate for 112 hours at 25.degree. C. The solution
was added to methanol using a Waring blender to precipitate the
polymer, which was filtered and vacuum dried. About 50 percent of
the chloromethyl groups had been replaced with acryloyl groups. The
product had the following formula: ##STR74##
POLYMER SYNTHESIS EXAMPLE XXV
A polymer of the formula ##STR75##
wherein n represents the number of repeating monomer units was
prepared as follows. A 1-liter, 3-neck round-bottom flask equipped
with a Dean-Stark (Barrett) trap, condenser, mechanical stirrer,
argon inlet, and stopper was situated in a silicone oil bath.
4,4'-Difluorobenzophenone (Aldrich Chemical Co., Milwaukee, Wis.,
16.59 grams), bisphenol A (Aldrich 14.18 grams, 0.065 mol),
potassium carbonate (21.6 grams), anhydrous N,N-dimethylacetamide
(100 milliliters), and toluene (30 milliliters) were added to the
flask and heated to 175.degree. C. (oil bath temperature) while the
volatile toluene component was collected and removed. After 4 hours
of heating at 175.degree. C. with continuous stirring, the reaction
mixture was allowed to cool to 25.degree. C. The solidified mass
was treated with acetic acid (vinegar) and extracted with methylene
chloride, filtered, and added to methanol to precipitate the
polymer, which was collected by filtration, washed with water, and
then washed with methanol. The yield of vacuum dried product,
poly(4-FPK-BPA), was 12.22 grams. The polymer was analyzed by gel
permeation chromatography (gpc) (elution solvent was
tetrahydrofuran) with the following results: M.sub.n 5,158,
M.sub.peak 15,080, M.sub.w 17,260, and M.sub.z+1 39,287. To obtain
a lower molecular weight, the reaction can be repeated with a 15
mol % offset in stoichiometry.
POLYMER SYNTHESIS EXAMPLE XXVI
A polymer of the formula ##STR76##
wherein n represents the number of repeating monomer units was
prepared as follows. A 250 milliliter, 3-neck round-bottom flask
equipped with a Dean-Stark (Barrett) trap, condenser, mechanical
stirrer, argon inlet, and stopper was situated in a silicone oil
bath. 4'-Methylbenzoyl-2,4-dichlorobenzene (0.0325 mol, 8.6125
grams), bis-phenol A (Aldrich 23,965-8, 0.035 mol, 7.99 grams),
potassium carbonate (10.7 grams), anhydrous N,N-dimethylacetamide
(60 milliliters), and toluene (60 milliliters, 49.1 grams) were
added to the flask and heated to 175.degree. C. (oil bath
temperature) while the volatile toluene component was collected and
removed. After 24 hours of heating at 175.degree. C. with
continuous stirring, the reaction product was filtered and the
filtrate was added to methanol to precipitate the polymer. The wet
polymer cake was isolated by filtration, washed with water, then
washed with methanol, and thereafter vacuum dried. The polymer
(7.70 grams, 48% yield) was analyzed by gel permeation
chromatography (gpc) (elution solvent was tetrahydrofuran) with the
following results: M.sub.n 1,898, M.sub.peak 2,154, M.sub.w 2,470,
M.sub.z 3,220, and M.sub.z+1 4,095.
POLYMER SYNTHESIS EXAMPLE XXVII
A polymer of the formula ##STR77##
wherein n represents the number of repeating monomer units was
prepared by repeating the process of Polymer Synthesis Example XXVI
except that the 4'-methylbenzoyl-2,4-dichlorobenzene starting
material was replaced with 8.16 grams (0.0325 mol) of
benzoyl-2,4-dichlorobenzene and the oil bath was heated to
170.degree. C. for 24 hours.
POLYMER SYNTHESIS EXAMPLE XXVIII
Chloromethylated phenoxy resins, polyethersulfones, and
polyphenylene oxides are prepared by reacting the unsubstituted
polymers with fin tetrachloride and 1-chloromethoxy-4-chlorobutane
as described by W. H. Daly et al. in Polymer Preprints, 20(1), 835
(1979), the disclosure of which is totally incorporated herein by
reference. The chloromethylation of polyethersulfone and
polyphenylene oxide can also be accomplished as described by V.
Percec et al. in Makromol. Chem., 185, 2319 (1984), the disclosure
of which is totally incorporated herein by reference.
Acryloylated polymers are then prepared as follows: ##STR78##
The chloromethylated polymers are acryloylated by allowing the
chloromethylated polymer (10 grams) in N,N-dimethylacetamide (71
milliliters) to react with acrylic acid sodium salt (5.14 grams)
for between 3 and 20 days, depending on the degree of acryloylation
desired. Longer reaction times result in increased acrylate
functionality.
POLYMER SYNTHESIS EXAMPLE XXIX
Poly(4-CPK-BPA) is made with a number average molecular weight of
2,800 as follows. A 5-liter, 3-neck round-bottom flask equipped
with a Dean-Stark (Barrett) trap, condenser, mechanical stirrer,
argon inlet, and stopper is situated in a silicone oil bath.
4,4-Dichlorobenzophenone (Aldrich 11,370, Aldrich Chemical Co.,
Milwaukee, Wis., 250 grams), bis-phenol A (Aldrich 23,965-8, 244.8
grams). potassium carbonate (327.8 grams), anhydrous
N,N-dimethylacetamide (1,500 milliliters), and toluene (275
milliliters) are added to the flask and heated to 175.degree. C.
(oil bath temperature) while the volatile toluene component is
collected and removed. After hours of heating 30 hours at
175.degree. C. with continuous stirring, the reaction mixture is
filtered to remove insoluble salts, and the resultant solution is
added to methanol (5 gallons) to precipitate the polymer. The
polymer is isolated by filtration, and the wet filter cake is
washed with water (3 gallons) and then with methanol (3 gallons).
The yield is about 360 grams of vacuum dried polymer. It is
believed that if the molecular weight of the polymer is determined
by gel permeation chromatography (gpc) (elution solvent was
tetrahydrofuran) the following results will be obtained: M.sub.n
2,800, M.sub.peak 5,800, M.sub.w 6,500, M.sub.z 12,000 and
M.sub.z+1 17,700. As a result of the stoichiometries used in the
reaction, it is believed that this polymer has end groups derived
from bis-phenol A.
The polymer is then chloromethylated as follows. A solution of
chloromethyl ether in methyl acetate is made by adding 282.68 grams
(256 milliliters) of acetyl chloride to a mixture of dimethoxy
methane (313.6 grams, 366.8 milliliters) and methanol (10
milliliters) in a 5-liter 3-neck round-bottom flask equipped with a
mechanical stirrer, argon inlet, reflux condenser, and addition
funnel. The solution is diluted with 1,066.8 milliliters of
1,1,2,2-tetrachloroethane and then tin tetrachloride (2.4
milliliters) is added via a gas-tight syringe, along with
1,1,2,2-tetrachloroethane (133.2 milliliters) using an addition
funnel. The reaction solution is heated to 50.degree. C. and a
solution of poly(4-CPK-BPA) (160.8 grams) in
1,1,2,2-tetrachloroethane (1,000 milliliters) is rapidly added. The
reaction mixture is then heated to reflux with an oil bath set at
110.degree. C. After four hours reflux with continuous stirring,
heating is discontinued and the mixture is allowed to cool to
25.degree. C. The reaction mixture is transferred in stages to a 2
liter round bottom flask and concentrated using a rotary evaporator
with gentle heating up to 50.degree. C. and reduced pressure
maintained with a vacuum pump trapped with liquid nitrogen. The
concentrate is added to methanol (6 gallons) to precipitate the
polymer using a Waring blender. The polymer is isolated by
filtration and vacuum dried to yield 200 grams of poly(4-CPK-BPA)
with 1.5 chloromethyl groups per repeat unit. Solvent free polymer
is obtained by reprecipitation of the polymer (75 grams) dissolved
in methylene chloride (500 grams) into methanol (3 gallons)
followed by filtration and vacuum drying to yield 70.5 grams (99.6%
yield) of solvent free polymer. To a solution of the
chloromethylated poly(4-CPK-BPA) (192 mmol of chloromethyl groups)
in 80 milliliters of dioxane is added 12 grams (46 mmol) of
triphenylphosphine. After 15 hours of reflux with mechanical
stirring and cooling to 25.degree. C., the polymer solidifies and
the mixture is extracted with diethyl ether using a Waring blender.
The yellow product is filtered, washed several times with diethyl
ether, and vacuum dried. To a solution of triphenylphosphonium
chloride salt of chloromethylated poly(4-CPK-BPA) (14 mmol of
phosphonium groups) in 200 milliliters of methanol, 2 milliliters
of Triton B (40 weight percent aqueous solution) and 11.5
milliliters (140 mmol) of formaldehyde (37 weight percent aqueous
solution) are added. The stirred reaction mixture is treated slowly
with 36 milliliters of 50 weight percent aqueous sodium hydroxide.
A precipitate starts to appear on addition of the first drops of
sodium hydroxide solution. After 10 hours of reaction at 25.degree.
C., the precipitate is filtered and vacuum dried. The separated
polymer is dissolved in methylene chloride, washed several times
with water, and then precipitated with methanol. Alternatively, to
a solution of solution of 1.8 mmol of phosphonium groups of the
triphenylphosphonium chloride salt chloromethylated poly(4-CPK-BPA)
in 40 milliliters of methylene chloride at ice-water temperature,
1.6 milliliters (19.5 mmol) of formaldehyde (37 weight percent
aqueous solution), and 0.4 milliliters of Triton-B (40 weight
percent aqueous solution) is added. The stirred reaction mixture is
treated slowly with 5 milliliters (62.5 mmol) of 50 weight percent
aqueous sodium hydroxide. After all the hydroxide solution is
added, the reaction mixture is allowed to react at 25.degree. C.
After 7 hours of reaction, the organic layer is separated, washed
with dilute hydrochloric acid, then washed with water, and then
precipitated into methanol from chloroform. The polymer has the
structure: ##STR79##
Other embodiments and modifications of the present invention may
occur to those of ordinary skill in the art subsequent to a review
of the information presented herein; these embodiments and
modifications, as well as equivalents thereof, are also included
within the scope of this invention.
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